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kernel-ark/net/packet/af_packet.c
Willem de Bruijn 61fad6816f net/packet: tpacket_rcv: avoid a producer race condition 
PACKET_RX_RING can cause multiple writers to access the same slot if a
fast writer wraps the ring while a slow writer is still copying. This
is particularly likely with few, large, slots (e.g., GSO packets).

Synchronize kernel thread ownership of rx ring slots with a bitmap.

Writers acquire a slot race-free by testing tp_status TP_STATUS_KERNEL
while holding the sk receive queue lock. They release this lock before
copying and set tp_status to TP_STATUS_USER to release to userspace
when done. During copying, another writer may take the lock, also see
TP_STATUS_KERNEL, and start writing to the same slot.

Introduce a new rx_owner_map bitmap with a bit per slot. To acquire a
slot, test and set with the lock held. To release race-free, update
tp_status and owner bit as a transaction, so take the lock again.

This is the one of a variety of discussed options (see Link below):

* instead of a shadow ring, embed the data in the slot itself, such as
in tp_padding. But any test for this field may match a value left by
userspace, causing deadlock.

* avoid the lock on release. This leaves a small race if releasing the
shadow slot before setting TP_STATUS_USER. The below reproducer showed
that this race is not academic. If releasing the slot after tp_status,
the race is more subtle. See the first link for details.

* add a new tp_status TP_KERNEL_OWNED to avoid the transactional store
of two fields. But, legacy applications may interpret all non-zero
tp_status as owned by the user. As libpcap does. So this is possible
only opt-in by newer processes. It can be added as an optional mode.

* embed the struct at the tail of pg_vec to avoid extra allocation.
The implementation proved no less complex than a separate field.

The additional locking cost on release adds contention, no different
than scaling on multicore or multiqueue h/w. In practice, below
reproducer nor small packet tcpdump showed a noticeable change in
perf report in cycles spent in spinlock. Where contention is
problematic, packet sockets support mitigation through PACKET_FANOUT.
And we can consider adding opt-in state TP_KERNEL_OWNED.

Easy to reproduce by running multiple netperf or similar TCP_STREAM
flows concurrently with `tcpdump -B 129 -n greater 60000`.

Based on an earlier patchset by Jon Rosen. See links below.

I believe this issue goes back to the introduction of tpacket_rcv,
which predates git history.

Link: https://www.mail-archive.com/netdev@vger.kernel.org/msg237222.html
Suggested-by: Jon Rosen <jrosen@cisco.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jon Rosen <jrosen@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-15 00:25:25 -07:00

4691 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* PACKET - implements raw packet sockets.
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Alan Cox, <gw4pts@gw4pts.ampr.org>
*
* Fixes:
* Alan Cox : verify_area() now used correctly
* Alan Cox : new skbuff lists, look ma no backlogs!
* Alan Cox : tidied skbuff lists.
* Alan Cox : Now uses generic datagram routines I
* added. Also fixed the peek/read crash
* from all old Linux datagram code.
* Alan Cox : Uses the improved datagram code.
* Alan Cox : Added NULL's for socket options.
* Alan Cox : Re-commented the code.
* Alan Cox : Use new kernel side addressing
* Rob Janssen : Correct MTU usage.
* Dave Platt : Counter leaks caused by incorrect
* interrupt locking and some slightly
* dubious gcc output. Can you read
* compiler: it said _VOLATILE_
* Richard Kooijman : Timestamp fixes.
* Alan Cox : New buffers. Use sk->mac.raw.
* Alan Cox : sendmsg/recvmsg support.
* Alan Cox : Protocol setting support
* Alexey Kuznetsov : Untied from IPv4 stack.
* Cyrus Durgin : Fixed kerneld for kmod.
* Michal Ostrowski : Module initialization cleanup.
* Ulises Alonso : Frame number limit removal and
* packet_set_ring memory leak.
* Eric Biederman : Allow for > 8 byte hardware addresses.
* The convention is that longer addresses
* will simply extend the hardware address
* byte arrays at the end of sockaddr_ll
* and packet_mreq.
* Johann Baudy : Added TX RING.
* Chetan Loke : Implemented TPACKET_V3 block abstraction
* layer.
* Copyright (C) 2011, <lokec@ccs.neu.edu>
*/
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/capability.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_packet.h>
#include <linux/wireless.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/uaccess.h>
#include <asm/ioctls.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/io.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/if_vlan.h>
#include <linux/virtio_net.h>
#include <linux/errqueue.h>
#include <linux/net_tstamp.h>
#include <linux/percpu.h>
#ifdef CONFIG_INET
#include <net/inet_common.h>
#endif
#include <linux/bpf.h>
#include <net/compat.h>
#include "internal.h"
/*
Assumptions:
- if device has no dev->hard_header routine, it adds and removes ll header
inside itself. In this case ll header is invisible outside of device,
but higher levels still should reserve dev->hard_header_len.
Some devices are enough clever to reallocate skb, when header
will not fit to reserved space (tunnel), another ones are silly
(PPP).
- packet socket receives packets with pulled ll header,
so that SOCK_RAW should push it back.
On receive:
-----------
Incoming, dev->hard_header!=NULL
mac_header -> ll header
data -> data
Outgoing, dev->hard_header!=NULL
mac_header -> ll header
data -> ll header
Incoming, dev->hard_header==NULL
mac_header -> UNKNOWN position. It is very likely, that it points to ll
header. PPP makes it, that is wrong, because introduce
assymetry between rx and tx paths.
data -> data
Outgoing, dev->hard_header==NULL
mac_header -> data. ll header is still not built!
data -> data
Resume
If dev->hard_header==NULL we are unlikely to restore sensible ll header.
On transmit:
------------
dev->hard_header != NULL
mac_header -> ll header
data -> ll header
dev->hard_header == NULL (ll header is added by device, we cannot control it)
mac_header -> data
data -> data
We should set nh.raw on output to correct posistion,
packet classifier depends on it.
*/
/* Private packet socket structures. */
/* identical to struct packet_mreq except it has
* a longer address field.
*/
struct packet_mreq_max {
int mr_ifindex;
unsigned short mr_type;
unsigned short mr_alen;
unsigned char mr_address[MAX_ADDR_LEN];
};
union tpacket_uhdr {
struct tpacket_hdr *h1;
struct tpacket2_hdr *h2;
struct tpacket3_hdr *h3;
void *raw;
};
static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
int closing, int tx_ring);
#define V3_ALIGNMENT (8)
#define BLK_HDR_LEN (ALIGN(sizeof(struct tpacket_block_desc), V3_ALIGNMENT))
#define BLK_PLUS_PRIV(sz_of_priv) \
(BLK_HDR_LEN + ALIGN((sz_of_priv), V3_ALIGNMENT))
#define BLOCK_STATUS(x) ((x)->hdr.bh1.block_status)
#define BLOCK_NUM_PKTS(x) ((x)->hdr.bh1.num_pkts)
#define BLOCK_O2FP(x) ((x)->hdr.bh1.offset_to_first_pkt)
#define BLOCK_LEN(x) ((x)->hdr.bh1.blk_len)
#define BLOCK_SNUM(x) ((x)->hdr.bh1.seq_num)
#define BLOCK_O2PRIV(x) ((x)->offset_to_priv)
#define BLOCK_PRIV(x) ((void *)((char *)(x) + BLOCK_O2PRIV(x)))
struct packet_sock;
static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev);
static void *packet_previous_frame(struct packet_sock *po,
struct packet_ring_buffer *rb,
int status);
static void packet_increment_head(struct packet_ring_buffer *buff);
static int prb_curr_blk_in_use(struct tpacket_block_desc *);
static void *prb_dispatch_next_block(struct tpacket_kbdq_core *,
struct packet_sock *);
static void prb_retire_current_block(struct tpacket_kbdq_core *,
struct packet_sock *, unsigned int status);
static int prb_queue_frozen(struct tpacket_kbdq_core *);
static void prb_open_block(struct tpacket_kbdq_core *,
struct tpacket_block_desc *);
static void prb_retire_rx_blk_timer_expired(struct timer_list *);
static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *);
static void prb_fill_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hdr *);
static void prb_clear_rxhash(struct tpacket_kbdq_core *,
struct tpacket3_hdr *);
static void prb_fill_vlan_info(struct tpacket_kbdq_core *,
struct tpacket3_hdr *);
static void packet_flush_mclist(struct sock *sk);
static u16 packet_pick_tx_queue(struct sk_buff *skb);
struct packet_skb_cb {
union {
struct sockaddr_pkt pkt;
union {
/* Trick: alias skb original length with
* ll.sll_family and ll.protocol in order
* to save room.
*/
unsigned int origlen;
struct sockaddr_ll ll;
};
} sa;
};
#define vio_le() virtio_legacy_is_little_endian()
#define PACKET_SKB_CB(__skb) ((struct packet_skb_cb *)((__skb)->cb))
#define GET_PBDQC_FROM_RB(x) ((struct tpacket_kbdq_core *)(&(x)->prb_bdqc))
#define GET_PBLOCK_DESC(x, bid) \
((struct tpacket_block_desc *)((x)->pkbdq[(bid)].buffer))
#define GET_CURR_PBLOCK_DESC_FROM_CORE(x) \
((struct tpacket_block_desc *)((x)->pkbdq[(x)->kactive_blk_num].buffer))
#define GET_NEXT_PRB_BLK_NUM(x) \
(((x)->kactive_blk_num < ((x)->knum_blocks-1)) ? \
((x)->kactive_blk_num+1) : 0)
static void __fanout_unlink(struct sock *sk, struct packet_sock *po);
static void __fanout_link(struct sock *sk, struct packet_sock *po);
static int packet_direct_xmit(struct sk_buff *skb)
{
return dev_direct_xmit(skb, packet_pick_tx_queue(skb));
}
static struct net_device *packet_cached_dev_get(struct packet_sock *po)
{
struct net_device *dev;
rcu_read_lock();
dev = rcu_dereference(po->cached_dev);
if (likely(dev))
dev_hold(dev);
rcu_read_unlock();
return dev;
}
static void packet_cached_dev_assign(struct packet_sock *po,
struct net_device *dev)
{
rcu_assign_pointer(po->cached_dev, dev);
}
static void packet_cached_dev_reset(struct packet_sock *po)
{
RCU_INIT_POINTER(po->cached_dev, NULL);
}
static bool packet_use_direct_xmit(const struct packet_sock *po)
{
return po->xmit == packet_direct_xmit;
}
static u16 packet_pick_tx_queue(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
const struct net_device_ops *ops = dev->netdev_ops;
int cpu = raw_smp_processor_id();
u16 queue_index;
#ifdef CONFIG_XPS
skb->sender_cpu = cpu + 1;
#endif
skb_record_rx_queue(skb, cpu % dev->real_num_tx_queues);
if (ops->ndo_select_queue) {
queue_index = ops->ndo_select_queue(dev, skb, NULL);
queue_index = netdev_cap_txqueue(dev, queue_index);
} else {
queue_index = netdev_pick_tx(dev, skb, NULL);
}
return queue_index;
}
/* __register_prot_hook must be invoked through register_prot_hook
* or from a context in which asynchronous accesses to the packet
* socket is not possible (packet_create()).
*/
static void __register_prot_hook(struct sock *sk)
{
struct packet_sock *po = pkt_sk(sk);
if (!po->running) {
if (po->fanout)
__fanout_link(sk, po);
else
dev_add_pack(&po->prot_hook);
sock_hold(sk);
po->running = 1;
}
}
static void register_prot_hook(struct sock *sk)
{
lockdep_assert_held_once(&pkt_sk(sk)->bind_lock);
__register_prot_hook(sk);
}
/* If the sync parameter is true, we will temporarily drop
* the po->bind_lock and do a synchronize_net to make sure no
* asynchronous packet processing paths still refer to the elements
* of po->prot_hook. If the sync parameter is false, it is the
* callers responsibility to take care of this.
*/
static void __unregister_prot_hook(struct sock *sk, bool sync)
{
struct packet_sock *po = pkt_sk(sk);
lockdep_assert_held_once(&po->bind_lock);
po->running = 0;
if (po->fanout)
__fanout_unlink(sk, po);
else
__dev_remove_pack(&po->prot_hook);
__sock_put(sk);
if (sync) {
spin_unlock(&po->bind_lock);
synchronize_net();
spin_lock(&po->bind_lock);
}
}
static void unregister_prot_hook(struct sock *sk, bool sync)
{
struct packet_sock *po = pkt_sk(sk);
if (po->running)
__unregister_prot_hook(sk, sync);
}
static inline struct page * __pure pgv_to_page(void *addr)
{
if (is_vmalloc_addr(addr))
return vmalloc_to_page(addr);
return virt_to_page(addr);
}
static void __packet_set_status(struct packet_sock *po, void *frame, int status)
{
union tpacket_uhdr h;
h.raw = frame;
switch (po->tp_version) {
case TPACKET_V1:
h.h1->tp_status = status;
flush_dcache_page(pgv_to_page(&h.h1->tp_status));
break;
case TPACKET_V2:
h.h2->tp_status = status;
flush_dcache_page(pgv_to_page(&h.h2->tp_status));
break;
case TPACKET_V3:
h.h3->tp_status = status;
flush_dcache_page(pgv_to_page(&h.h3->tp_status));
break;
default:
WARN(1, "TPACKET version not supported.\n");
BUG();
}
smp_wmb();
}
static int __packet_get_status(const struct packet_sock *po, void *frame)
{
union tpacket_uhdr h;
smp_rmb();
h.raw = frame;
switch (po->tp_version) {
case TPACKET_V1:
flush_dcache_page(pgv_to_page(&h.h1->tp_status));
return h.h1->tp_status;
case TPACKET_V2:
flush_dcache_page(pgv_to_page(&h.h2->tp_status));
return h.h2->tp_status;
case TPACKET_V3:
flush_dcache_page(pgv_to_page(&h.h3->tp_status));
return h.h3->tp_status;
default:
WARN(1, "TPACKET version not supported.\n");
BUG();
return 0;
}
}
static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec64 *ts,
unsigned int flags)
{
struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
if (shhwtstamps &&
(flags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
ktime_to_timespec64_cond(shhwtstamps->hwtstamp, ts))
return TP_STATUS_TS_RAW_HARDWARE;
if (ktime_to_timespec64_cond(skb->tstamp, ts))
return TP_STATUS_TS_SOFTWARE;
return 0;
}
static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame,
struct sk_buff *skb)
{
union tpacket_uhdr h;
struct timespec64 ts;
__u32 ts_status;
if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
return 0;
h.raw = frame;
/*
* versions 1 through 3 overflow the timestamps in y2106, since they
* all store the seconds in a 32-bit unsigned integer.
* If we create a version 4, that should have a 64-bit timestamp,
* either 64-bit seconds + 32-bit nanoseconds, or just 64-bit
* nanoseconds.
*/
switch (po->tp_version) {
case TPACKET_V1:
h.h1->tp_sec = ts.tv_sec;
h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
break;
case TPACKET_V2:
h.h2->tp_sec = ts.tv_sec;
h.h2->tp_nsec = ts.tv_nsec;
break;
case TPACKET_V3:
h.h3->tp_sec = ts.tv_sec;
h.h3->tp_nsec = ts.tv_nsec;
break;
default:
WARN(1, "TPACKET version not supported.\n");
BUG();
}
/* one flush is safe, as both fields always lie on the same cacheline */
flush_dcache_page(pgv_to_page(&h.h1->tp_sec));
smp_wmb();
return ts_status;
}
static void *packet_lookup_frame(const struct packet_sock *po,
const struct packet_ring_buffer *rb,
unsigned int position,
int status)
{
unsigned int pg_vec_pos, frame_offset;
union tpacket_uhdr h;
pg_vec_pos = position / rb->frames_per_block;
frame_offset = position % rb->frames_per_block;
h.raw = rb->pg_vec[pg_vec_pos].buffer +
(frame_offset * rb->frame_size);
if (status != __packet_get_status(po, h.raw))
return NULL;
return h.raw;
}
static void *packet_current_frame(struct packet_sock *po,
struct packet_ring_buffer *rb,
int status)
{
return packet_lookup_frame(po, rb, rb->head, status);
}
static void prb_del_retire_blk_timer(struct tpacket_kbdq_core *pkc)
{
del_timer_sync(&pkc->retire_blk_timer);
}
static void prb_shutdown_retire_blk_timer(struct packet_sock *po,
struct sk_buff_head *rb_queue)
{
struct tpacket_kbdq_core *pkc;
pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
spin_lock_bh(&rb_queue->lock);
pkc->delete_blk_timer = 1;
spin_unlock_bh(&rb_queue->lock);
prb_del_retire_blk_timer(pkc);
}
static void prb_setup_retire_blk_timer(struct packet_sock *po)
{
struct tpacket_kbdq_core *pkc;
pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
timer_setup(&pkc->retire_blk_timer, prb_retire_rx_blk_timer_expired,
0);
pkc->retire_blk_timer.expires = jiffies;
}
static int prb_calc_retire_blk_tmo(struct packet_sock *po,
int blk_size_in_bytes)
{
struct net_device *dev;
unsigned int mbits, div;
struct ethtool_link_ksettings ecmd;
int err;
rtnl_lock();
dev = __dev_get_by_index(sock_net(&po->sk), po->ifindex);
if (unlikely(!dev)) {
rtnl_unlock();
return DEFAULT_PRB_RETIRE_TOV;
}
err = __ethtool_get_link_ksettings(dev, &ecmd);
rtnl_unlock();
if (err)
return DEFAULT_PRB_RETIRE_TOV;
/* If the link speed is so slow you don't really
* need to worry about perf anyways
*/
if (ecmd.base.speed < SPEED_1000 ||
ecmd.base.speed == SPEED_UNKNOWN)
return DEFAULT_PRB_RETIRE_TOV;
div = ecmd.base.speed / 1000;
mbits = (blk_size_in_bytes * 8) / (1024 * 1024);
if (div)
mbits /= div;
if (div)
return mbits + 1;
return mbits;
}
static void prb_init_ft_ops(struct tpacket_kbdq_core *p1,
union tpacket_req_u *req_u)
{
p1->feature_req_word = req_u->req3.tp_feature_req_word;
}
static void init_prb_bdqc(struct packet_sock *po,
struct packet_ring_buffer *rb,
struct pgv *pg_vec,
union tpacket_req_u *req_u)
{
struct tpacket_kbdq_core *p1 = GET_PBDQC_FROM_RB(rb);
struct tpacket_block_desc *pbd;
memset(p1, 0x0, sizeof(*p1));
p1->knxt_seq_num = 1;
p1->pkbdq = pg_vec;
pbd = (struct tpacket_block_desc *)pg_vec[0].buffer;
p1->pkblk_start = pg_vec[0].buffer;
p1->kblk_size = req_u->req3.tp_block_size;
p1->knum_blocks = req_u->req3.tp_block_nr;
p1->hdrlen = po->tp_hdrlen;
p1->version = po->tp_version;
p1->last_kactive_blk_num = 0;
po->stats.stats3.tp_freeze_q_cnt = 0;
if (req_u->req3.tp_retire_blk_tov)
p1->retire_blk_tov = req_u->req3.tp_retire_blk_tov;
else
p1->retire_blk_tov = prb_calc_retire_blk_tmo(po,
req_u->req3.tp_block_size);
p1->tov_in_jiffies = msecs_to_jiffies(p1->retire_blk_tov);
p1->blk_sizeof_priv = req_u->req3.tp_sizeof_priv;
p1->max_frame_len = p1->kblk_size - BLK_PLUS_PRIV(p1->blk_sizeof_priv);
prb_init_ft_ops(p1, req_u);
prb_setup_retire_blk_timer(po);
prb_open_block(p1, pbd);
}
/* Do NOT update the last_blk_num first.
* Assumes sk_buff_head lock is held.
*/
static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *pkc)
{
mod_timer(&pkc->retire_blk_timer,
jiffies + pkc->tov_in_jiffies);
pkc->last_kactive_blk_num = pkc->kactive_blk_num;
}
/*
* Timer logic:
* 1) We refresh the timer only when we open a block.
* By doing this we don't waste cycles refreshing the timer
* on packet-by-packet basis.
*
* With a 1MB block-size, on a 1Gbps line, it will take
* i) ~8 ms to fill a block + ii) memcpy etc.
* In this cut we are not accounting for the memcpy time.
*
* So, if the user sets the 'tmo' to 10ms then the timer
* will never fire while the block is still getting filled
* (which is what we want). However, the user could choose
* to close a block early and that's fine.
*
* But when the timer does fire, we check whether or not to refresh it.
* Since the tmo granularity is in msecs, it is not too expensive
* to refresh the timer, lets say every '8' msecs.
* Either the user can set the 'tmo' or we can derive it based on
* a) line-speed and b) block-size.
* prb_calc_retire_blk_tmo() calculates the tmo.
*
*/
static void prb_retire_rx_blk_timer_expired(struct timer_list *t)
{
struct packet_sock *po =
from_timer(po, t, rx_ring.prb_bdqc.retire_blk_timer);
struct tpacket_kbdq_core *pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
unsigned int frozen;
struct tpacket_block_desc *pbd;
spin_lock(&po->sk.sk_receive_queue.lock);
frozen = prb_queue_frozen(pkc);
pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
if (unlikely(pkc->delete_blk_timer))
goto out;
/* We only need to plug the race when the block is partially filled.
* tpacket_rcv:
* lock(); increment BLOCK_NUM_PKTS; unlock()
* copy_bits() is in progress ...
* timer fires on other cpu:
* we can't retire the current block because copy_bits
* is in progress.
*
*/
if (BLOCK_NUM_PKTS(pbd)) {
while (atomic_read(&pkc->blk_fill_in_prog)) {
/* Waiting for skb_copy_bits to finish... */
cpu_relax();
}
}
if (pkc->last_kactive_blk_num == pkc->kactive_blk_num) {
if (!frozen) {
if (!BLOCK_NUM_PKTS(pbd)) {
/* An empty block. Just refresh the timer. */
goto refresh_timer;
}
prb_retire_current_block(pkc, po, TP_STATUS_BLK_TMO);
if (!prb_dispatch_next_block(pkc, po))
goto refresh_timer;
else
goto out;
} else {
/* Case 1. Queue was frozen because user-space was
* lagging behind.
*/
if (prb_curr_blk_in_use(pbd)) {
/*
* Ok, user-space is still behind.
* So just refresh the timer.
*/
goto refresh_timer;
} else {
/* Case 2. queue was frozen,user-space caught up,
* now the link went idle && the timer fired.
* We don't have a block to close.So we open this
* block and restart the timer.
* opening a block thaws the queue,restarts timer
* Thawing/timer-refresh is a side effect.
*/
prb_open_block(pkc, pbd);
goto out;
}
}
}
refresh_timer:
_prb_refresh_rx_retire_blk_timer(pkc);
out:
spin_unlock(&po->sk.sk_receive_queue.lock);
}
static void prb_flush_block(struct tpacket_kbdq_core *pkc1,
struct tpacket_block_desc *pbd1, __u32 status)
{
/* Flush everything minus the block header */
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
u8 *start, *end;
start = (u8 *)pbd1;
/* Skip the block header(we know header WILL fit in 4K) */
start += PAGE_SIZE;
end = (u8 *)PAGE_ALIGN((unsigned long)pkc1->pkblk_end);
for (; start < end; start += PAGE_SIZE)
flush_dcache_page(pgv_to_page(start));
smp_wmb();
#endif
/* Now update the block status. */
BLOCK_STATUS(pbd1) = status;
/* Flush the block header */
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
start = (u8 *)pbd1;
flush_dcache_page(pgv_to_page(start));
smp_wmb();
#endif
}
/*
* Side effect:
*
* 1) flush the block
* 2) Increment active_blk_num
*
* Note:We DONT refresh the timer on purpose.
* Because almost always the next block will be opened.
*/
static void prb_close_block(struct tpacket_kbdq_core *pkc1,
struct tpacket_block_desc *pbd1,
struct packet_sock *po, unsigned int stat)
{
__u32 status = TP_STATUS_USER | stat;
struct tpacket3_hdr *last_pkt;
struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
struct sock *sk = &po->sk;
if (atomic_read(&po->tp_drops))
status |= TP_STATUS_LOSING;
last_pkt = (struct tpacket3_hdr *)pkc1->prev;
last_pkt->tp_next_offset = 0;
/* Get the ts of the last pkt */
if (BLOCK_NUM_PKTS(pbd1)) {
h1->ts_last_pkt.ts_sec = last_pkt->tp_sec;
h1->ts_last_pkt.ts_nsec = last_pkt->tp_nsec;
} else {
/* Ok, we tmo'd - so get the current time.
*
* It shouldn't really happen as we don't close empty
* blocks. See prb_retire_rx_blk_timer_expired().
*/
struct timespec64 ts;
ktime_get_real_ts64(&ts);
h1->ts_last_pkt.ts_sec = ts.tv_sec;
h1->ts_last_pkt.ts_nsec = ts.tv_nsec;
}
smp_wmb();
/* Flush the block */
prb_flush_block(pkc1, pbd1, status);
sk->sk_data_ready(sk);
pkc1->kactive_blk_num = GET_NEXT_PRB_BLK_NUM(pkc1);
}
static void prb_thaw_queue(struct tpacket_kbdq_core *pkc)
{
pkc->reset_pending_on_curr_blk = 0;
}
/*
* Side effect of opening a block:
*
* 1) prb_queue is thawed.
* 2) retire_blk_timer is refreshed.
*
*/
static void prb_open_block(struct tpacket_kbdq_core *pkc1,
struct tpacket_block_desc *pbd1)
{
struct timespec64 ts;
struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
smp_rmb();
/* We could have just memset this but we will lose the
* flexibility of making the priv area sticky
*/
BLOCK_SNUM(pbd1) = pkc1->knxt_seq_num++;
BLOCK_NUM_PKTS(pbd1) = 0;
BLOCK_LEN(pbd1) = BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
ktime_get_real_ts64(&ts);
h1->ts_first_pkt.ts_sec = ts.tv_sec;
h1->ts_first_pkt.ts_nsec = ts.tv_nsec;
pkc1->pkblk_start = (char *)pbd1;
pkc1->nxt_offset = pkc1->pkblk_start + BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
BLOCK_O2FP(pbd1) = (__u32)BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
BLOCK_O2PRIV(pbd1) = BLK_HDR_LEN;
pbd1->version = pkc1->version;
pkc1->prev = pkc1->nxt_offset;
pkc1->pkblk_end = pkc1->pkblk_start + pkc1->kblk_size;
prb_thaw_queue(pkc1);
_prb_refresh_rx_retire_blk_timer(pkc1);
smp_wmb();
}
/*
* Queue freeze logic:
* 1) Assume tp_block_nr = 8 blocks.
* 2) At time 't0', user opens Rx ring.
* 3) Some time past 't0', kernel starts filling blocks starting from 0 .. 7
* 4) user-space is either sleeping or processing block '0'.
* 5) tpacket_rcv is currently filling block '7', since there is no space left,
* it will close block-7,loop around and try to fill block '0'.
* call-flow:
* __packet_lookup_frame_in_block
* prb_retire_current_block()
* prb_dispatch_next_block()
* |->(BLOCK_STATUS == USER) evaluates to true
* 5.1) Since block-0 is currently in-use, we just freeze the queue.
* 6) Now there are two cases:
* 6.1) Link goes idle right after the queue is frozen.
* But remember, the last open_block() refreshed the timer.
* When this timer expires,it will refresh itself so that we can
* re-open block-0 in near future.
* 6.2) Link is busy and keeps on receiving packets. This is a simple
* case and __packet_lookup_frame_in_block will check if block-0
* is free and can now be re-used.
*/
static void prb_freeze_queue(struct tpacket_kbdq_core *pkc,
struct packet_sock *po)
{
pkc->reset_pending_on_curr_blk = 1;
po->stats.stats3.tp_freeze_q_cnt++;
}
#define TOTAL_PKT_LEN_INCL_ALIGN(length) (ALIGN((length), V3_ALIGNMENT))
/*
* If the next block is free then we will dispatch it
* and return a good offset.
* Else, we will freeze the queue.
* So, caller must check the return value.
*/
static void *prb_dispatch_next_block(struct tpacket_kbdq_core *pkc,
struct packet_sock *po)
{
struct tpacket_block_desc *pbd;
smp_rmb();
/* 1. Get current block num */
pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
/* 2. If this block is currently in_use then freeze the queue */
if (TP_STATUS_USER & BLOCK_STATUS(pbd)) {
prb_freeze_queue(pkc, po);
return NULL;
}
/*
* 3.
* open this block and return the offset where the first packet
* needs to get stored.
*/
prb_open_block(pkc, pbd);
return (void *)pkc->nxt_offset;
}
static void prb_retire_current_block(struct tpacket_kbdq_core *pkc,
struct packet_sock *po, unsigned int status)
{
struct tpacket_block_desc *pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
/* retire/close the current block */
if (likely(TP_STATUS_KERNEL == BLOCK_STATUS(pbd))) {
/*
* Plug the case where copy_bits() is in progress on
* cpu-0 and tpacket_rcv() got invoked on cpu-1, didn't
* have space to copy the pkt in the current block and
* called prb_retire_current_block()
*
* We don't need to worry about the TMO case because
* the timer-handler already handled this case.
*/
if (!(status & TP_STATUS_BLK_TMO)) {
while (atomic_read(&pkc->blk_fill_in_prog)) {
/* Waiting for skb_copy_bits to finish... */
cpu_relax();
}
}
prb_close_block(pkc, pbd, po, status);
return;
}
}
static int prb_curr_blk_in_use(struct tpacket_block_desc *pbd)
{
return TP_STATUS_USER & BLOCK_STATUS(pbd);
}
static int prb_queue_frozen(struct tpacket_kbdq_core *pkc)
{
return pkc->reset_pending_on_curr_blk;
}
static void prb_clear_blk_fill_status(struct packet_ring_buffer *rb)
{
struct tpacket_kbdq_core *pkc = GET_PBDQC_FROM_RB(rb);
atomic_dec(&pkc->blk_fill_in_prog);
}
static void prb_fill_rxhash(struct tpacket_kbdq_core *pkc,
struct tpacket3_hdr *ppd)
{
ppd->hv1.tp_rxhash = skb_get_hash(pkc->skb);
}
static void prb_clear_rxhash(struct tpacket_kbdq_core *pkc,
struct tpacket3_hdr *ppd)
{
ppd->hv1.tp_rxhash = 0;
}
static void prb_fill_vlan_info(struct tpacket_kbdq_core *pkc,
struct tpacket3_hdr *ppd)
{
if (skb_vlan_tag_present(pkc->skb)) {
ppd->hv1.tp_vlan_tci = skb_vlan_tag_get(pkc->skb);
ppd->hv1.tp_vlan_tpid = ntohs(pkc->skb->vlan_proto);
ppd->tp_status = TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
} else {
ppd->hv1.tp_vlan_tci = 0;
ppd->hv1.tp_vlan_tpid = 0;
ppd->tp_status = TP_STATUS_AVAILABLE;
}
}
static void prb_run_all_ft_ops(struct tpacket_kbdq_core *pkc,
struct tpacket3_hdr *ppd)
{
ppd->hv1.tp_padding = 0;
prb_fill_vlan_info(pkc, ppd);
if (pkc->feature_req_word & TP_FT_REQ_FILL_RXHASH)
prb_fill_rxhash(pkc, ppd);
else
prb_clear_rxhash(pkc, ppd);
}
static void prb_fill_curr_block(char *curr,
struct tpacket_kbdq_core *pkc,
struct tpacket_block_desc *pbd,
unsigned int len)
{
struct tpacket3_hdr *ppd;
ppd = (struct tpacket3_hdr *)curr;
ppd->tp_next_offset = TOTAL_PKT_LEN_INCL_ALIGN(len);
pkc->prev = curr;
pkc->nxt_offset += TOTAL_PKT_LEN_INCL_ALIGN(len);
BLOCK_LEN(pbd) += TOTAL_PKT_LEN_INCL_ALIGN(len);
BLOCK_NUM_PKTS(pbd) += 1;
atomic_inc(&pkc->blk_fill_in_prog);
prb_run_all_ft_ops(pkc, ppd);
}
/* Assumes caller has the sk->rx_queue.lock */
static void *__packet_lookup_frame_in_block(struct packet_sock *po,
struct sk_buff *skb,
unsigned int len
)
{
struct tpacket_kbdq_core *pkc;
struct tpacket_block_desc *pbd;
char *curr, *end;
pkc = GET_PBDQC_FROM_RB(&po->rx_ring);
pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
/* Queue is frozen when user space is lagging behind */
if (prb_queue_frozen(pkc)) {
/*
* Check if that last block which caused the queue to freeze,
* is still in_use by user-space.
*/
if (prb_curr_blk_in_use(pbd)) {
/* Can't record this packet */
return NULL;
} else {
/*
* Ok, the block was released by user-space.
* Now let's open that block.
* opening a block also thaws the queue.
* Thawing is a side effect.
*/
prb_open_block(pkc, pbd);
}
}
smp_mb();
curr = pkc->nxt_offset;
pkc->skb = skb;
end = (char *)pbd + pkc->kblk_size;
/* first try the current block */
if (curr+TOTAL_PKT_LEN_INCL_ALIGN(len) < end) {
prb_fill_curr_block(curr, pkc, pbd, len);
return (void *)curr;
}
/* Ok, close the current block */
prb_retire_current_block(pkc, po, 0);
/* Now, try to dispatch the next block */
curr = (char *)prb_dispatch_next_block(pkc, po);
if (curr) {
pbd = GET_CURR_PBLOCK_DESC_FROM_CORE(pkc);
prb_fill_curr_block(curr, pkc, pbd, len);
return (void *)curr;
}
/*
* No free blocks are available.user_space hasn't caught up yet.
* Queue was just frozen and now this packet will get dropped.
*/
return NULL;
}
static void *packet_current_rx_frame(struct packet_sock *po,
struct sk_buff *skb,
int status, unsigned int len)
{
char *curr = NULL;
switch (po->tp_version) {
case TPACKET_V1:
case TPACKET_V2:
curr = packet_lookup_frame(po, &po->rx_ring,
po->rx_ring.head, status);
return curr;
case TPACKET_V3:
return __packet_lookup_frame_in_block(po, skb, len);
default:
WARN(1, "TPACKET version not supported\n");
BUG();
return NULL;
}
}
static void *prb_lookup_block(const struct packet_sock *po,
const struct packet_ring_buffer *rb,
unsigned int idx,
int status)
{
struct tpacket_kbdq_core *pkc = GET_PBDQC_FROM_RB(rb);
struct tpacket_block_desc *pbd = GET_PBLOCK_DESC(pkc, idx);
if (status != BLOCK_STATUS(pbd))
return NULL;
return pbd;
}
static int prb_previous_blk_num(struct packet_ring_buffer *rb)
{
unsigned int prev;
if (rb->prb_bdqc.kactive_blk_num)
prev = rb->prb_bdqc.kactive_blk_num-1;
else
prev = rb->prb_bdqc.knum_blocks-1;
return prev;
}
/* Assumes caller has held the rx_queue.lock */
static void *__prb_previous_block(struct packet_sock *po,
struct packet_ring_buffer *rb,
int status)
{
unsigned int previous = prb_previous_blk_num(rb);
return prb_lookup_block(po, rb, previous, status);
}
static void *packet_previous_rx_frame(struct packet_sock *po,
struct packet_ring_buffer *rb,
int status)
{
if (po->tp_version <= TPACKET_V2)
return packet_previous_frame(po, rb, status);
return __prb_previous_block(po, rb, status);
}
static void packet_increment_rx_head(struct packet_sock *po,
struct packet_ring_buffer *rb)
{
switch (po->tp_version) {
case TPACKET_V1:
case TPACKET_V2:
return packet_increment_head(rb);
case TPACKET_V3:
default:
WARN(1, "TPACKET version not supported.\n");
BUG();
return;
}
}
static void *packet_previous_frame(struct packet_sock *po,
struct packet_ring_buffer *rb,
int status)
{
unsigned int previous = rb->head ? rb->head - 1 : rb->frame_max;
return packet_lookup_frame(po, rb, previous, status);
}
static void packet_increment_head(struct packet_ring_buffer *buff)
{
buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
}
static void packet_inc_pending(struct packet_ring_buffer *rb)
{
this_cpu_inc(*rb->pending_refcnt);
}
static void packet_dec_pending(struct packet_ring_buffer *rb)
{
this_cpu_dec(*rb->pending_refcnt);
}
static unsigned int packet_read_pending(const struct packet_ring_buffer *rb)
{
unsigned int refcnt = 0;
int cpu;
/* We don't use pending refcount in rx_ring. */
if (rb->pending_refcnt == NULL)
return 0;
for_each_possible_cpu(cpu)
refcnt += *per_cpu_ptr(rb->pending_refcnt, cpu);
return refcnt;
}
static int packet_alloc_pending(struct packet_sock *po)
{
po->rx_ring.pending_refcnt = NULL;
po->tx_ring.pending_refcnt = alloc_percpu(unsigned int);
if (unlikely(po->tx_ring.pending_refcnt == NULL))
return -ENOBUFS;
return 0;
}
static void packet_free_pending(struct packet_sock *po)
{
free_percpu(po->tx_ring.pending_refcnt);
}
#define ROOM_POW_OFF 2
#define ROOM_NONE 0x0
#define ROOM_LOW 0x1
#define ROOM_NORMAL 0x2
static bool __tpacket_has_room(const struct packet_sock *po, int pow_off)
{
int idx, len;
len = READ_ONCE(po->rx_ring.frame_max) + 1;
idx = READ_ONCE(po->rx_ring.head);
if (pow_off)
idx += len >> pow_off;
if (idx >= len)
idx -= len;
return packet_lookup_frame(po, &po->rx_ring, idx, TP_STATUS_KERNEL);
}
static bool __tpacket_v3_has_room(const struct packet_sock *po, int pow_off)
{
int idx, len;
len = READ_ONCE(po->rx_ring.prb_bdqc.knum_blocks);
idx = READ_ONCE(po->rx_ring.prb_bdqc.kactive_blk_num);
if (pow_off)
idx += len >> pow_off;
if (idx >= len)
idx -= len;
return prb_lookup_block(po, &po->rx_ring, idx, TP_STATUS_KERNEL);
}
static int __packet_rcv_has_room(const struct packet_sock *po,
const struct sk_buff *skb)
{
const struct sock *sk = &po->sk;
int ret = ROOM_NONE;
if (po->prot_hook.func != tpacket_rcv) {
int rcvbuf = READ_ONCE(sk->sk_rcvbuf);
int avail = rcvbuf - atomic_read(&sk->sk_rmem_alloc)
- (skb ? skb->truesize : 0);
if (avail > (rcvbuf >> ROOM_POW_OFF))
return ROOM_NORMAL;
else if (avail > 0)
return ROOM_LOW;
else
return ROOM_NONE;
}
if (po->tp_version == TPACKET_V3) {
if (__tpacket_v3_has_room(po, ROOM_POW_OFF))
ret = ROOM_NORMAL;
else if (__tpacket_v3_has_room(po, 0))
ret = ROOM_LOW;
} else {
if (__tpacket_has_room(po, ROOM_POW_OFF))
ret = ROOM_NORMAL;
else if (__tpacket_has_room(po, 0))
ret = ROOM_LOW;
}
return ret;
}
static int packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
{
int pressure, ret;
ret = __packet_rcv_has_room(po, skb);
pressure = ret != ROOM_NORMAL;
if (READ_ONCE(po->pressure) != pressure)
WRITE_ONCE(po->pressure, pressure);
return ret;
}
static void packet_rcv_try_clear_pressure(struct packet_sock *po)
{
if (READ_ONCE(po->pressure) &&
__packet_rcv_has_room(po, NULL) == ROOM_NORMAL)
WRITE_ONCE(po->pressure, 0);
}
static void packet_sock_destruct(struct sock *sk)
{
skb_queue_purge(&sk->sk_error_queue);
WARN_ON(atomic_read(&sk->sk_rmem_alloc));
WARN_ON(refcount_read(&sk->sk_wmem_alloc));
if (!sock_flag(sk, SOCK_DEAD)) {
pr_err("Attempt to release alive packet socket: %p\n", sk);
return;
}
sk_refcnt_debug_dec(sk);
}
static bool fanout_flow_is_huge(struct packet_sock *po, struct sk_buff *skb)
{
u32 *history = po->rollover->history;
u32 victim, rxhash;
int i, count = 0;
rxhash = skb_get_hash(skb);
for (i = 0; i < ROLLOVER_HLEN; i++)
if (READ_ONCE(history[i]) == rxhash)
count++;
victim = prandom_u32() % ROLLOVER_HLEN;
/* Avoid dirtying the cache line if possible */
if (READ_ONCE(history[victim]) != rxhash)
WRITE_ONCE(history[victim], rxhash);
return count > (ROLLOVER_HLEN >> 1);
}
static unsigned int fanout_demux_hash(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
{
return reciprocal_scale(__skb_get_hash_symmetric(skb), num);
}
static unsigned int fanout_demux_lb(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
{
unsigned int val = atomic_inc_return(&f->rr_cur);
return val % num;
}
static unsigned int fanout_demux_cpu(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
{
return smp_processor_id() % num;
}
static unsigned int fanout_demux_rnd(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
{
return prandom_u32_max(num);
}
static unsigned int fanout_demux_rollover(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int idx, bool try_self,
unsigned int num)
{
struct packet_sock *po, *po_next, *po_skip = NULL;
unsigned int i, j, room = ROOM_NONE;
po = pkt_sk(f->arr[idx]);
if (try_self) {
room = packet_rcv_has_room(po, skb);
if (room == ROOM_NORMAL ||
(room == ROOM_LOW && !fanout_flow_is_huge(po, skb)))
return idx;
po_skip = po;
}
i = j = min_t(int, po->rollover->sock, num - 1);
do {
po_next = pkt_sk(f->arr[i]);
if (po_next != po_skip && !READ_ONCE(po_next->pressure) &&
packet_rcv_has_room(po_next, skb) == ROOM_NORMAL) {
if (i != j)
po->rollover->sock = i;
atomic_long_inc(&po->rollover->num);
if (room == ROOM_LOW)
atomic_long_inc(&po->rollover->num_huge);
return i;
}
if (++i == num)
i = 0;
} while (i != j);
atomic_long_inc(&po->rollover->num_failed);
return idx;
}
static unsigned int fanout_demux_qm(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
{
return skb_get_queue_mapping(skb) % num;
}
static unsigned int fanout_demux_bpf(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
{
struct bpf_prog *prog;
unsigned int ret = 0;
rcu_read_lock();
prog = rcu_dereference(f->bpf_prog);
if (prog)
ret = bpf_prog_run_clear_cb(prog, skb) % num;
rcu_read_unlock();
return ret;
}
static bool fanout_has_flag(struct packet_fanout *f, u16 flag)
{
return f->flags & (flag >> 8);
}
static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct packet_fanout *f = pt->af_packet_priv;
unsigned int num = READ_ONCE(f->num_members);
struct net *net = read_pnet(&f->net);
struct packet_sock *po;
unsigned int idx;
if (!net_eq(dev_net(dev), net) || !num) {
kfree_skb(skb);
return 0;
}
if (fanout_has_flag(f, PACKET_FANOUT_FLAG_DEFRAG)) {
skb = ip_check_defrag(net, skb, IP_DEFRAG_AF_PACKET);
if (!skb)
return 0;
}
switch (f->type) {
case PACKET_FANOUT_HASH:
default:
idx = fanout_demux_hash(f, skb, num);
break;
case PACKET_FANOUT_LB:
idx = fanout_demux_lb(f, skb, num);
break;
case PACKET_FANOUT_CPU:
idx = fanout_demux_cpu(f, skb, num);
break;
case PACKET_FANOUT_RND:
idx = fanout_demux_rnd(f, skb, num);
break;
case PACKET_FANOUT_QM:
idx = fanout_demux_qm(f, skb, num);
break;
case PACKET_FANOUT_ROLLOVER:
idx = fanout_demux_rollover(f, skb, 0, false, num);
break;
case PACKET_FANOUT_CBPF:
case PACKET_FANOUT_EBPF:
idx = fanout_demux_bpf(f, skb, num);
break;
}
if (fanout_has_flag(f, PACKET_FANOUT_FLAG_ROLLOVER))
idx = fanout_demux_rollover(f, skb, idx, true, num);
po = pkt_sk(f->arr[idx]);
return po->prot_hook.func(skb, dev, &po->prot_hook, orig_dev);
}
DEFINE_MUTEX(fanout_mutex);
EXPORT_SYMBOL_GPL(fanout_mutex);
static LIST_HEAD(fanout_list);
static u16 fanout_next_id;
static void __fanout_link(struct sock *sk, struct packet_sock *po)
{
struct packet_fanout *f = po->fanout;
spin_lock(&f->lock);
f->arr[f->num_members] = sk;
smp_wmb();
f->num_members++;
if (f->num_members == 1)
dev_add_pack(&f->prot_hook);
spin_unlock(&f->lock);
}
static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
{
struct packet_fanout *f = po->fanout;
int i;
spin_lock(&f->lock);
for (i = 0; i < f->num_members; i++) {
if (f->arr[i] == sk)
break;
}
BUG_ON(i >= f->num_members);
f->arr[i] = f->arr[f->num_members - 1];
f->num_members--;
if (f->num_members == 0)
__dev_remove_pack(&f->prot_hook);
spin_unlock(&f->lock);
}
static bool match_fanout_group(struct packet_type *ptype, struct sock *sk)
{
if (sk->sk_family != PF_PACKET)
return false;
return ptype->af_packet_priv == pkt_sk(sk)->fanout;
}
static void fanout_init_data(struct packet_fanout *f)
{
switch (f->type) {
case PACKET_FANOUT_LB:
atomic_set(&f->rr_cur, 0);
break;
case PACKET_FANOUT_CBPF:
case PACKET_FANOUT_EBPF:
RCU_INIT_POINTER(f->bpf_prog, NULL);
break;
}
}
static void __fanout_set_data_bpf(struct packet_fanout *f, struct bpf_prog *new)
{
struct bpf_prog *old;
spin_lock(&f->lock);
old = rcu_dereference_protected(f->bpf_prog, lockdep_is_held(&f->lock));
rcu_assign_pointer(f->bpf_prog, new);
spin_unlock(&f->lock);
if (old) {
synchronize_net();
bpf_prog_destroy(old);
}
}
static int fanout_set_data_cbpf(struct packet_sock *po, char __user *data,
unsigned int len)
{
struct bpf_prog *new;
struct sock_fprog fprog;
int ret;
if (sock_flag(&po->sk, SOCK_FILTER_LOCKED))
return -EPERM;
if (len != sizeof(fprog))
return -EINVAL;
if (copy_from_user(&fprog, data, len))
return -EFAULT;
ret = bpf_prog_create_from_user(&new, &fprog, NULL, false);
if (ret)
return ret;
__fanout_set_data_bpf(po->fanout, new);
return 0;
}
static int fanout_set_data_ebpf(struct packet_sock *po, char __user *data,
unsigned int len)
{
struct bpf_prog *new;
u32 fd;
if (sock_flag(&po->sk, SOCK_FILTER_LOCKED))
return -EPERM;
if (len != sizeof(fd))
return -EINVAL;
if (copy_from_user(&fd, data, len))
return -EFAULT;
new = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
if (IS_ERR(new))
return PTR_ERR(new);
__fanout_set_data_bpf(po->fanout, new);
return 0;
}
static int fanout_set_data(struct packet_sock *po, char __user *data,
unsigned int len)
{
switch (po->fanout->type) {
case PACKET_FANOUT_CBPF:
return fanout_set_data_cbpf(po, data, len);
case PACKET_FANOUT_EBPF:
return fanout_set_data_ebpf(po, data, len);
default:
return -EINVAL;
}
}
static void fanout_release_data(struct packet_fanout *f)
{
switch (f->type) {
case PACKET_FANOUT_CBPF:
case PACKET_FANOUT_EBPF:
__fanout_set_data_bpf(f, NULL);
}
}
static bool __fanout_id_is_free(struct sock *sk, u16 candidate_id)
{
struct packet_fanout *f;
list_for_each_entry(f, &fanout_list, list) {
if (f->id == candidate_id &&
read_pnet(&f->net) == sock_net(sk)) {
return false;
}
}
return true;
}
static bool fanout_find_new_id(struct sock *sk, u16 *new_id)
{
u16 id = fanout_next_id;
do {
if (__fanout_id_is_free(sk, id)) {
*new_id = id;
fanout_next_id = id + 1;
return true;
}
id++;
} while (id != fanout_next_id);
return false;
}
static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
{
struct packet_rollover *rollover = NULL;
struct packet_sock *po = pkt_sk(sk);
struct packet_fanout *f, *match;
u8 type = type_flags & 0xff;
u8 flags = type_flags >> 8;
int err;
switch (type) {
case PACKET_FANOUT_ROLLOVER:
if (type_flags & PACKET_FANOUT_FLAG_ROLLOVER)
return -EINVAL;
case PACKET_FANOUT_HASH:
case PACKET_FANOUT_LB:
case PACKET_FANOUT_CPU:
case PACKET_FANOUT_RND:
case PACKET_FANOUT_QM:
case PACKET_FANOUT_CBPF:
case PACKET_FANOUT_EBPF:
break;
default:
return -EINVAL;
}
mutex_lock(&fanout_mutex);
err = -EALREADY;
if (po->fanout)
goto out;
if (type == PACKET_FANOUT_ROLLOVER ||
(type_flags & PACKET_FANOUT_FLAG_ROLLOVER)) {
err = -ENOMEM;
rollover = kzalloc(sizeof(*rollover), GFP_KERNEL);
if (!rollover)
goto out;
atomic_long_set(&rollover->num, 0);
atomic_long_set(&rollover->num_huge, 0);
atomic_long_set(&rollover->num_failed, 0);
}
if (type_flags & PACKET_FANOUT_FLAG_UNIQUEID) {
if (id != 0) {
err = -EINVAL;
goto out;
}
if (!fanout_find_new_id(sk, &id)) {
err = -ENOMEM;
goto out;
}
/* ephemeral flag for the first socket in the group: drop it */
flags &= ~(PACKET_FANOUT_FLAG_UNIQUEID >> 8);
}
match = NULL;
list_for_each_entry(f, &fanout_list, list) {
if (f->id == id &&
read_pnet(&f->net) == sock_net(sk)) {
match = f;
break;
}
}
err = -EINVAL;
if (match && match->flags != flags)
goto out;
if (!match) {
err = -ENOMEM;
match = kzalloc(sizeof(*match), GFP_KERNEL);
if (!match)
goto out;
write_pnet(&match->net, sock_net(sk));
match->id = id;
match->type = type;
match->flags = flags;
INIT_LIST_HEAD(&match->list);
spin_lock_init(&match->lock);
refcount_set(&match->sk_ref, 0);
fanout_init_data(match);
match->prot_hook.type = po->prot_hook.type;
match->prot_hook.dev = po->prot_hook.dev;
match->prot_hook.func = packet_rcv_fanout;
match->prot_hook.af_packet_priv = match;
match->prot_hook.id_match = match_fanout_group;
list_add(&match->list, &fanout_list);
}
err = -EINVAL;
spin_lock(&po->bind_lock);
if (po->running &&
match->type == type &&
match->prot_hook.type == po->prot_hook.type &&
match->prot_hook.dev == po->prot_hook.dev) {
err = -ENOSPC;
if (refcount_read(&match->sk_ref) < PACKET_FANOUT_MAX) {
__dev_remove_pack(&po->prot_hook);
po->fanout = match;
po->rollover = rollover;
rollover = NULL;
refcount_set(&match->sk_ref, refcount_read(&match->sk_ref) + 1);
__fanout_link(sk, po);
err = 0;
}
}
spin_unlock(&po->bind_lock);
if (err && !refcount_read(&match->sk_ref)) {
list_del(&match->list);
kfree(match);
}
out:
kfree(rollover);
mutex_unlock(&fanout_mutex);
return err;
}
/* If pkt_sk(sk)->fanout->sk_ref is zero, this function removes
* pkt_sk(sk)->fanout from fanout_list and returns pkt_sk(sk)->fanout.
* It is the responsibility of the caller to call fanout_release_data() and
* free the returned packet_fanout (after synchronize_net())
*/
static struct packet_fanout *fanout_release(struct sock *sk)
{
struct packet_sock *po = pkt_sk(sk);
struct packet_fanout *f;
mutex_lock(&fanout_mutex);
f = po->fanout;
if (f) {
po->fanout = NULL;
if (refcount_dec_and_test(&f->sk_ref))
list_del(&f->list);
else
f = NULL;
}
mutex_unlock(&fanout_mutex);
return f;
}
static bool packet_extra_vlan_len_allowed(const struct net_device *dev,
struct sk_buff *skb)
{
/* Earlier code assumed this would be a VLAN pkt, double-check
* this now that we have the actual packet in hand. We can only
* do this check on Ethernet devices.
*/
if (unlikely(dev->type != ARPHRD_ETHER))
return false;
skb_reset_mac_header(skb);
return likely(eth_hdr(skb)->h_proto == htons(ETH_P_8021Q));
}
static const struct proto_ops packet_ops;
static const struct proto_ops packet_ops_spkt;
static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct sock *sk;
struct sockaddr_pkt *spkt;
/*
* When we registered the protocol we saved the socket in the data
* field for just this event.
*/
sk = pt->af_packet_priv;
/*
* Yank back the headers [hope the device set this
* right or kerboom...]
*
* Incoming packets have ll header pulled,
* push it back.
*
* For outgoing ones skb->data == skb_mac_header(skb)
* so that this procedure is noop.
*/
if (skb->pkt_type == PACKET_LOOPBACK)
goto out;
if (!net_eq(dev_net(dev), sock_net(sk)))
goto out;
skb = skb_share_check(skb, GFP_ATOMIC);
if (skb == NULL)
goto oom;
/* drop any routing info */
skb_dst_drop(skb);
/* drop conntrack reference */
nf_reset_ct(skb);
spkt = &PACKET_SKB_CB(skb)->sa.pkt;
skb_push(skb, skb->data - skb_mac_header(skb));
/*
* The SOCK_PACKET socket receives _all_ frames.
*/
spkt->spkt_family = dev->type;
strlcpy(spkt->spkt_device, dev->name, sizeof(spkt->spkt_device));
spkt->spkt_protocol = skb->protocol;
/*
* Charge the memory to the socket. This is done specifically
* to prevent sockets using all the memory up.
*/
if (sock_queue_rcv_skb(sk, skb) == 0)
return 0;
out:
kfree_skb(skb);
oom:
return 0;
}
static void packet_parse_headers(struct sk_buff *skb, struct socket *sock)
{
if ((!skb->protocol || skb->protocol == htons(ETH_P_ALL)) &&
sock->type == SOCK_RAW) {
skb_reset_mac_header(skb);
skb->protocol = dev_parse_header_protocol(skb);
}
skb_probe_transport_header(skb);
}
/*
* Output a raw packet to a device layer. This bypasses all the other
* protocol layers and you must therefore supply it with a complete frame
*/
static int packet_sendmsg_spkt(struct socket *sock, struct msghdr *msg,
size_t len)
{
struct sock *sk = sock->sk;
DECLARE_SOCKADDR(struct sockaddr_pkt *, saddr, msg->msg_name);
struct sk_buff *skb = NULL;
struct net_device *dev;
struct sockcm_cookie sockc;
__be16 proto = 0;
int err;
int extra_len = 0;
/*
* Get and verify the address.
*/
if (saddr) {
if (msg->msg_namelen < sizeof(struct sockaddr))
return -EINVAL;
if (msg->msg_namelen == sizeof(struct sockaddr_pkt))
proto = saddr->spkt_protocol;
} else
return -ENOTCONN; /* SOCK_PACKET must be sent giving an address */
/*
* Find the device first to size check it
*/
saddr->spkt_device[sizeof(saddr->spkt_device) - 1] = 0;
retry:
rcu_read_lock();
dev = dev_get_by_name_rcu(sock_net(sk), saddr->spkt_device);
err = -ENODEV;
if (dev == NULL)
goto out_unlock;
err = -ENETDOWN;
if (!(dev->flags & IFF_UP))
goto out_unlock;
/*
* You may not queue a frame bigger than the mtu. This is the lowest level
* raw protocol and you must do your own fragmentation at this level.
*/
if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
if (!netif_supports_nofcs(dev)) {
err = -EPROTONOSUPPORT;
goto out_unlock;
}
extra_len = 4; /* We're doing our own CRC */
}
err = -EMSGSIZE;
if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN + extra_len)
goto out_unlock;
if (!skb) {
size_t reserved = LL_RESERVED_SPACE(dev);
int tlen = dev->needed_tailroom;
unsigned int hhlen = dev->header_ops ? dev->hard_header_len : 0;
rcu_read_unlock();
skb = sock_wmalloc(sk, len + reserved + tlen, 0, GFP_KERNEL);
if (skb == NULL)
return -ENOBUFS;
/* FIXME: Save some space for broken drivers that write a hard
* header at transmission time by themselves. PPP is the notable
* one here. This should really be fixed at the driver level.
*/
skb_reserve(skb, reserved);
skb_reset_network_header(skb);
/* Try to align data part correctly */
if (hhlen) {
skb->data -= hhlen;
skb->tail -= hhlen;
if (len < hhlen)
skb_reset_network_header(skb);
}
err = memcpy_from_msg(skb_put(skb, len), msg, len);
if (err)
goto out_free;
goto retry;
}
if (!dev_validate_header(dev, skb->data, len)) {
err = -EINVAL;
goto out_unlock;
}
if (len > (dev->mtu + dev->hard_header_len + extra_len) &&
!packet_extra_vlan_len_allowed(dev, skb)) {
err = -EMSGSIZE;
goto out_unlock;
}
sockcm_init(&sockc, sk);
if (msg->msg_controllen) {
err = sock_cmsg_send(sk, msg, &sockc);
if (unlikely(err))
goto out_unlock;
}
skb->protocol = proto;
skb->dev = dev;
skb->priority = sk->sk_priority;
skb->mark = sk->sk_mark;
skb->tstamp = sockc.transmit_time;
skb_setup_tx_timestamp(skb, sockc.tsflags);
if (unlikely(extra_len == 4))
skb->no_fcs = 1;
packet_parse_headers(skb, sock);
dev_queue_xmit(skb);
rcu_read_unlock();
return len;
out_unlock:
rcu_read_unlock();
out_free:
kfree_skb(skb);
return err;
}
static unsigned int run_filter(struct sk_buff *skb,
const struct sock *sk,
unsigned int res)
{
struct sk_filter *filter;
rcu_read_lock();
filter = rcu_dereference(sk->sk_filter);
if (filter != NULL)
res = bpf_prog_run_clear_cb(filter->prog, skb);
rcu_read_unlock();
return res;
}
static int packet_rcv_vnet(struct msghdr *msg, const struct sk_buff *skb,
size_t *len)
{
struct virtio_net_hdr vnet_hdr;
if (*len < sizeof(vnet_hdr))
return -EINVAL;
*len -= sizeof(vnet_hdr);
if (virtio_net_hdr_from_skb(skb, &vnet_hdr, vio_le(), true, 0))
return -EINVAL;
return memcpy_to_msg(msg, (void *)&vnet_hdr, sizeof(vnet_hdr));
}
/*
* This function makes lazy skb cloning in hope that most of packets
* are discarded by BPF.
*
* Note tricky part: we DO mangle shared skb! skb->data, skb->len
* and skb->cb are mangled. It works because (and until) packets
* falling here are owned by current CPU. Output packets are cloned
* by dev_queue_xmit_nit(), input packets are processed by net_bh
* sequencially, so that if we return skb to original state on exit,
* we will not harm anyone.
*/
static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct sock *sk;
struct sockaddr_ll *sll;
struct packet_sock *po;
u8 *skb_head = skb->data;
int skb_len = skb->len;
unsigned int snaplen, res;
bool is_drop_n_account = false;
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
sk = pt->af_packet_priv;
po = pkt_sk(sk);
if (!net_eq(dev_net(dev), sock_net(sk)))
goto drop;
skb->dev = dev;
if (dev->header_ops) {
/* The device has an explicit notion of ll header,
* exported to higher levels.
*
* Otherwise, the device hides details of its frame
* structure, so that corresponding packet head is
* never delivered to user.
*/
if (sk->sk_type != SOCK_DGRAM)
skb_push(skb, skb->data - skb_mac_header(skb));
else if (skb->pkt_type == PACKET_OUTGOING) {
/* Special case: outgoing packets have ll header at head */
skb_pull(skb, skb_network_offset(skb));
}
}
snaplen = skb->len;
res = run_filter(skb, sk, snaplen);
if (!res)
goto drop_n_restore;
if (snaplen > res)
snaplen = res;
if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
goto drop_n_acct;
if (skb_shared(skb)) {
struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
if (nskb == NULL)
goto drop_n_acct;
if (skb_head != skb->data) {
skb->data = skb_head;
skb->len = skb_len;
}
consume_skb(skb);
skb = nskb;
}
sock_skb_cb_check_size(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8);
sll = &PACKET_SKB_CB(skb)->sa.ll;
sll->sll_hatype = dev->type;
sll->sll_pkttype = skb->pkt_type;
if (unlikely(po->origdev))
sll->sll_ifindex = orig_dev->ifindex;
else
sll->sll_ifindex = dev->ifindex;
sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
/* sll->sll_family and sll->sll_protocol are set in packet_recvmsg().
* Use their space for storing the original skb length.
*/
PACKET_SKB_CB(skb)->sa.origlen = skb->len;
if (pskb_trim(skb, snaplen))
goto drop_n_acct;
skb_set_owner_r(skb, sk);
skb->dev = NULL;
skb_dst_drop(skb);
/* drop conntrack reference */
nf_reset_ct(skb);
spin_lock(&sk->sk_receive_queue.lock);
po->stats.stats1.tp_packets++;
sock_skb_set_dropcount(sk, skb);
__skb_queue_tail(&sk->sk_receive_queue, skb);
spin_unlock(&sk->sk_receive_queue.lock);
sk->sk_data_ready(sk);
return 0;
drop_n_acct:
is_drop_n_account = true;
atomic_inc(&po->tp_drops);
atomic_inc(&sk->sk_drops);
drop_n_restore:
if (skb_head != skb->data && skb_shared(skb)) {
skb->data = skb_head;
skb->len = skb_len;
}
drop:
if (!is_drop_n_account)
consume_skb(skb);
else
kfree_skb(skb);
return 0;
}
static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct sock *sk;
struct packet_sock *po;
struct sockaddr_ll *sll;
union tpacket_uhdr h;
u8 *skb_head = skb->data;
int skb_len = skb->len;
unsigned int snaplen, res;
unsigned long status = TP_STATUS_USER;
unsigned short macoff, netoff, hdrlen;
struct sk_buff *copy_skb = NULL;
struct timespec64 ts;
__u32 ts_status;
bool is_drop_n_account = false;
unsigned int slot_id = 0;
bool do_vnet = false;
/* struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT.
* We may add members to them until current aligned size without forcing
* userspace to call getsockopt(..., PACKET_HDRLEN, ...).
*/
BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h2)) != 32);
BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h3)) != 48);
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
sk = pt->af_packet_priv;
po = pkt_sk(sk);
if (!net_eq(dev_net(dev), sock_net(sk)))
goto drop;
if (dev->header_ops) {
if (sk->sk_type != SOCK_DGRAM)
skb_push(skb, skb->data - skb_mac_header(skb));
else if (skb->pkt_type == PACKET_OUTGOING) {
/* Special case: outgoing packets have ll header at head */
skb_pull(skb, skb_network_offset(skb));
}
}
snaplen = skb->len;
res = run_filter(skb, sk, snaplen);
if (!res)
goto drop_n_restore;
/* If we are flooded, just give up */
if (__packet_rcv_has_room(po, skb) == ROOM_NONE) {
atomic_inc(&po->tp_drops);
goto drop_n_restore;
}
if (skb->ip_summed == CHECKSUM_PARTIAL)
status |= TP_STATUS_CSUMNOTREADY;
else if (skb->pkt_type != PACKET_OUTGOING &&
(skb->ip_summed == CHECKSUM_COMPLETE ||
skb_csum_unnecessary(skb)))
status |= TP_STATUS_CSUM_VALID;
if (snaplen > res)
snaplen = res;
if (sk->sk_type == SOCK_DGRAM) {
macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16 +
po->tp_reserve;
} else {
unsigned int maclen = skb_network_offset(skb);
netoff = TPACKET_ALIGN(po->tp_hdrlen +
(maclen < 16 ? 16 : maclen)) +
po->tp_reserve;
if (po->has_vnet_hdr) {
netoff += sizeof(struct virtio_net_hdr);
do_vnet = true;
}
macoff = netoff - maclen;
}
if (po->tp_version <= TPACKET_V2) {
if (macoff + snaplen > po->rx_ring.frame_size) {
if (po->copy_thresh &&
atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {
if (skb_shared(skb)) {
copy_skb = skb_clone(skb, GFP_ATOMIC);
} else {
copy_skb = skb_get(skb);
skb_head = skb->data;
}
if (copy_skb)
skb_set_owner_r(copy_skb, sk);
}
snaplen = po->rx_ring.frame_size - macoff;
if ((int)snaplen < 0) {
snaplen = 0;
do_vnet = false;
}
}
} else if (unlikely(macoff + snaplen >
GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len)) {
u32 nval;
nval = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len - macoff;
pr_err_once("tpacket_rcv: packet too big, clamped from %u to %u. macoff=%u\n",
snaplen, nval, macoff);
snaplen = nval;
if (unlikely((int)snaplen < 0)) {
snaplen = 0;
macoff = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len;
do_vnet = false;
}
}
spin_lock(&sk->sk_receive_queue.lock);
h.raw = packet_current_rx_frame(po, skb,
TP_STATUS_KERNEL, (macoff+snaplen));
if (!h.raw)
goto drop_n_account;
if (po->tp_version <= TPACKET_V2) {
slot_id = po->rx_ring.head;
if (test_bit(slot_id, po->rx_ring.rx_owner_map))
goto drop_n_account;
__set_bit(slot_id, po->rx_ring.rx_owner_map);
}
if (do_vnet &&
virtio_net_hdr_from_skb(skb, h.raw + macoff -
sizeof(struct virtio_net_hdr),
vio_le(), true, 0))
goto drop_n_account;
if (po->tp_version <= TPACKET_V2) {
packet_increment_rx_head(po, &po->rx_ring);
/*
* LOSING will be reported till you read the stats,
* because it's COR - Clear On Read.
* Anyways, moving it for V1/V2 only as V3 doesn't need this
* at packet level.
*/
if (atomic_read(&po->tp_drops))
status |= TP_STATUS_LOSING;
}
po->stats.stats1.tp_packets++;
if (copy_skb) {
status |= TP_STATUS_COPY;
__skb_queue_tail(&sk->sk_receive_queue, copy_skb);
}
spin_unlock(&sk->sk_receive_queue.lock);
skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp)))
ktime_get_real_ts64(&ts);
status |= ts_status;
switch (po->tp_version) {
case TPACKET_V1:
h.h1->tp_len = skb->len;
h.h1->tp_snaplen = snaplen;
h.h1->tp_mac = macoff;
h.h1->tp_net = netoff;
h.h1->tp_sec = ts.tv_sec;
h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;
hdrlen = sizeof(*h.h1);
break;
case TPACKET_V2:
h.h2->tp_len = skb->len;
h.h2->tp_snaplen = snaplen;
h.h2->tp_mac = macoff;
h.h2->tp_net = netoff;
h.h2->tp_sec = ts.tv_sec;
h.h2->tp_nsec = ts.tv_nsec;
if (skb_vlan_tag_present(skb)) {
h.h2->tp_vlan_tci = skb_vlan_tag_get(skb);
h.h2->tp_vlan_tpid = ntohs(skb->vlan_proto);
status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
} else {
h.h2->tp_vlan_tci = 0;
h.h2->tp_vlan_tpid = 0;
}
memset(h.h2->tp_padding, 0, sizeof(h.h2->tp_padding));
hdrlen = sizeof(*h.h2);
break;
case TPACKET_V3:
/* tp_nxt_offset,vlan are already populated above.
* So DONT clear those fields here
*/
h.h3->tp_status |= status;
h.h3->tp_len = skb->len;
h.h3->tp_snaplen = snaplen;
h.h3->tp_mac = macoff;
h.h3->tp_net = netoff;
h.h3->tp_sec = ts.tv_sec;
h.h3->tp_nsec = ts.tv_nsec;
memset(h.h3->tp_padding, 0, sizeof(h.h3->tp_padding));
hdrlen = sizeof(*h.h3);
break;
default:
BUG();
}
sll = h.raw + TPACKET_ALIGN(hdrlen);
sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
sll->sll_family = AF_PACKET;
sll->sll_hatype = dev->type;
sll->sll_protocol = skb->protocol;
sll->sll_pkttype = skb->pkt_type;
if (unlikely(po->origdev))
sll->sll_ifindex = orig_dev->ifindex;
else
sll->sll_ifindex = dev->ifindex;
smp_mb();
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
if (po->tp_version <= TPACKET_V2) {
u8 *start, *end;
end = (u8 *) PAGE_ALIGN((unsigned long) h.raw +
macoff + snaplen);
for (start = h.raw; start < end; start += PAGE_SIZE)
flush_dcache_page(pgv_to_page(start));
}
smp_wmb();
#endif
if (po->tp_version <= TPACKET_V2) {
spin_lock(&sk->sk_receive_queue.lock);
__packet_set_status(po, h.raw, status);
__clear_bit(slot_id, po->rx_ring.rx_owner_map);
spin_unlock(&sk->sk_receive_queue.lock);
sk->sk_data_ready(sk);
} else {
prb_clear_blk_fill_status(&po->rx_ring);
}
drop_n_restore:
if (skb_head != skb->data && skb_shared(skb)) {
skb->data = skb_head;
skb->len = skb_len;
}
drop:
if (!is_drop_n_account)
consume_skb(skb);
else
kfree_skb(skb);
return 0;
drop_n_account:
spin_unlock(&sk->sk_receive_queue.lock);
atomic_inc(&po->tp_drops);
is_drop_n_account = true;
sk->sk_data_ready(sk);
kfree_skb(copy_skb);
goto drop_n_restore;
}
static void tpacket_destruct_skb(struct sk_buff *skb)
{
struct packet_sock *po = pkt_sk(skb->sk);
if (likely(po->tx_ring.pg_vec)) {
void *ph;
__u32 ts;
ph = skb_zcopy_get_nouarg(skb);
packet_dec_pending(&po->tx_ring);
ts = __packet_set_timestamp(po, ph, skb);
__packet_set_status(po, ph, TP_STATUS_AVAILABLE | ts);
if (!packet_read_pending(&po->tx_ring))
complete(&po->skb_completion);
}
sock_wfree(skb);
}
static int __packet_snd_vnet_parse(struct virtio_net_hdr *vnet_hdr, size_t len)
{
if ((vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
(__virtio16_to_cpu(vio_le(), vnet_hdr->csum_start) +
__virtio16_to_cpu(vio_le(), vnet_hdr->csum_offset) + 2 >
__virtio16_to_cpu(vio_le(), vnet_hdr->hdr_len)))
vnet_hdr->hdr_len = __cpu_to_virtio16(vio_le(),
__virtio16_to_cpu(vio_le(), vnet_hdr->csum_start) +
__virtio16_to_cpu(vio_le(), vnet_hdr->csum_offset) + 2);
if (__virtio16_to_cpu(vio_le(), vnet_hdr->hdr_len) > len)
return -EINVAL;
return 0;
}
static int packet_snd_vnet_parse(struct msghdr *msg, size_t *len,
struct virtio_net_hdr *vnet_hdr)
{
if (*len < sizeof(*vnet_hdr))
return -EINVAL;
*len -= sizeof(*vnet_hdr);
if (!copy_from_iter_full(vnet_hdr, sizeof(*vnet_hdr), &msg->msg_iter))
return -EFAULT;
return __packet_snd_vnet_parse(vnet_hdr, *len);
}
static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
void *frame, struct net_device *dev, void *data, int tp_len,
__be16 proto, unsigned char *addr, int hlen, int copylen,
const struct sockcm_cookie *sockc)
{
union tpacket_uhdr ph;
int to_write, offset, len, nr_frags, len_max;
struct socket *sock = po->sk.sk_socket;
struct page *page;
int err;
ph.raw = frame;
skb->protocol = proto;
skb->dev = dev;
skb->priority = po->sk.sk_priority;
skb->mark = po->sk.sk_mark;
skb->tstamp = sockc->transmit_time;
skb_setup_tx_timestamp(skb, sockc->tsflags);
skb_zcopy_set_nouarg(skb, ph.raw);
skb_reserve(skb, hlen);
skb_reset_network_header(skb);
to_write = tp_len;
if (sock->type == SOCK_DGRAM) {
err = dev_hard_header(skb, dev, ntohs(proto), addr,
NULL, tp_len);
if (unlikely(err < 0))
return -EINVAL;
} else if (copylen) {
int hdrlen = min_t(int, copylen, tp_len);
skb_push(skb, dev->hard_header_len);
skb_put(skb, copylen - dev->hard_header_len);
err = skb_store_bits(skb, 0, data, hdrlen);
if (unlikely(err))
return err;
if (!dev_validate_header(dev, skb->data, hdrlen))
return -EINVAL;
data += hdrlen;
to_write -= hdrlen;
}
offset = offset_in_page(data);
len_max = PAGE_SIZE - offset;
len = ((to_write > len_max) ? len_max : to_write);
skb->data_len = to_write;
skb->len += to_write;
skb->truesize += to_write;
refcount_add(to_write, &po->sk.sk_wmem_alloc);
while (likely(to_write)) {
nr_frags = skb_shinfo(skb)->nr_frags;
if (unlikely(nr_frags >= MAX_SKB_FRAGS)) {
pr_err("Packet exceed the number of skb frags(%lu)\n",
MAX_SKB_FRAGS);
return -EFAULT;
}
page = pgv_to_page(data);
data += len;
flush_dcache_page(page);
get_page(page);
skb_fill_page_desc(skb, nr_frags, page, offset, len);
to_write -= len;
offset = 0;
len_max = PAGE_SIZE;
len = ((to_write > len_max) ? len_max : to_write);
}
packet_parse_headers(skb, sock);
return tp_len;
}
static int tpacket_parse_header(struct packet_sock *po, void *frame,
int size_max, void **data)
{
union tpacket_uhdr ph;
int tp_len, off;
ph.raw = frame;
switch (po->tp_version) {
case TPACKET_V3:
if (ph.h3->tp_next_offset != 0) {
pr_warn_once("variable sized slot not supported");
return -EINVAL;
}
tp_len = ph.h3->tp_len;
break;
case TPACKET_V2:
tp_len = ph.h2->tp_len;
break;
default:
tp_len = ph.h1->tp_len;
break;
}
if (unlikely(tp_len > size_max)) {
pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
return -EMSGSIZE;
}
if (unlikely(po->tp_tx_has_off)) {
int off_min, off_max;
off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
off_max = po->tx_ring.frame_size - tp_len;
if (po->sk.sk_type == SOCK_DGRAM) {
switch (po->tp_version) {
case TPACKET_V3:
off = ph.h3->tp_net;
break;
case TPACKET_V2:
off = ph.h2->tp_net;
break;
default:
off = ph.h1->tp_net;
break;
}
} else {
switch (po->tp_version) {
case TPACKET_V3:
off = ph.h3->tp_mac;
break;
case TPACKET_V2:
off = ph.h2->tp_mac;
break;
default:
off = ph.h1->tp_mac;
break;
}
}
if (unlikely((off < off_min) || (off_max < off)))
return -EINVAL;
} else {
off = po->tp_hdrlen - sizeof(struct sockaddr_ll);
}
*data = frame + off;
return tp_len;
}
static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
{
struct sk_buff *skb = NULL;
struct net_device *dev;
struct virtio_net_hdr *vnet_hdr = NULL;
struct sockcm_cookie sockc;
__be16 proto;
int err, reserve = 0;
void *ph;
DECLARE_SOCKADDR(struct sockaddr_ll *, saddr, msg->msg_name);
bool need_wait = !(msg->msg_flags & MSG_DONTWAIT);
unsigned char *addr = NULL;
int tp_len, size_max;
void *data;
int len_sum = 0;
int status = TP_STATUS_AVAILABLE;
int hlen, tlen, copylen = 0;
long timeo = 0;
mutex_lock(&po->pg_vec_lock);
/* packet_sendmsg() check on tx_ring.pg_vec was lockless,
* we need to confirm it under protection of pg_vec_lock.
*/
if (unlikely(!po->tx_ring.pg_vec)) {
err = -EBUSY;
goto out;
}
if (likely(saddr == NULL)) {
dev = packet_cached_dev_get(po);
proto = po->num;
} else {
err = -EINVAL;
if (msg->msg_namelen < sizeof(struct sockaddr_ll))
goto out;
if (msg->msg_namelen < (saddr->sll_halen
+ offsetof(struct sockaddr_ll,
sll_addr)))
goto out;
proto = saddr->sll_protocol;
dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
if (po->sk.sk_socket->type == SOCK_DGRAM) {
if (dev && msg->msg_namelen < dev->addr_len +
offsetof(struct sockaddr_ll, sll_addr))
goto out_put;
addr = saddr->sll_addr;
}
}
err = -ENXIO;
if (unlikely(dev == NULL))
goto out;
err = -ENETDOWN;
if (unlikely(!(dev->flags & IFF_UP)))
goto out_put;
sockcm_init(&sockc, &po->sk);
if (msg->msg_controllen) {
err = sock_cmsg_send(&po->sk, msg, &sockc);
if (unlikely(err))
goto out_put;
}
if (po->sk.sk_socket->type == SOCK_RAW)
reserve = dev->hard_header_len;
size_max = po->tx_ring.frame_size
- (po->tp_hdrlen - sizeof(struct sockaddr_ll));
if ((size_max > dev->mtu + reserve + VLAN_HLEN) && !po->has_vnet_hdr)
size_max = dev->mtu + reserve + VLAN_HLEN;
reinit_completion(&po->skb_completion);
do {
ph = packet_current_frame(po, &po->tx_ring,
TP_STATUS_SEND_REQUEST);
if (unlikely(ph == NULL)) {
if (need_wait && skb) {
timeo = sock_sndtimeo(&po->sk, msg->msg_flags & MSG_DONTWAIT);
timeo = wait_for_completion_interruptible_timeout(&po->skb_completion, timeo);
if (timeo <= 0) {
err = !timeo ? -ETIMEDOUT : -ERESTARTSYS;
goto out_put;
}
}
/* check for additional frames */
continue;
}
skb = NULL;
tp_len = tpacket_parse_header(po, ph, size_max, &data);
if (tp_len < 0)
goto tpacket_error;
status = TP_STATUS_SEND_REQUEST;
hlen = LL_RESERVED_SPACE(dev);
tlen = dev->needed_tailroom;
if (po->has_vnet_hdr) {
vnet_hdr = data;
data += sizeof(*vnet_hdr);
tp_len -= sizeof(*vnet_hdr);
if (tp_len < 0 ||
__packet_snd_vnet_parse(vnet_hdr, tp_len)) {
tp_len = -EINVAL;
goto tpacket_error;
}
copylen = __virtio16_to_cpu(vio_le(),
vnet_hdr->hdr_len);
}
copylen = max_t(int, copylen, dev->hard_header_len);
skb = sock_alloc_send_skb(&po->sk,
hlen + tlen + sizeof(struct sockaddr_ll) +
(copylen - dev->hard_header_len),
!need_wait, &err);
if (unlikely(skb == NULL)) {
/* we assume the socket was initially writeable ... */
if (likely(len_sum > 0))
err = len_sum;
goto out_status;
}
tp_len = tpacket_fill_skb(po, skb, ph, dev, data, tp_len, proto,
addr, hlen, copylen, &sockc);
if (likely(tp_len >= 0) &&
tp_len > dev->mtu + reserve &&
!po->has_vnet_hdr &&
!packet_extra_vlan_len_allowed(dev, skb))
tp_len = -EMSGSIZE;
if (unlikely(tp_len < 0)) {
tpacket_error:
if (po->tp_loss) {
__packet_set_status(po, ph,
TP_STATUS_AVAILABLE);
packet_increment_head(&po->tx_ring);
kfree_skb(skb);
continue;
} else {
status = TP_STATUS_WRONG_FORMAT;
err = tp_len;
goto out_status;
}
}
if (po->has_vnet_hdr) {
if (virtio_net_hdr_to_skb(skb, vnet_hdr, vio_le())) {
tp_len = -EINVAL;
goto tpacket_error;
}
virtio_net_hdr_set_proto(skb, vnet_hdr);
}
skb->destructor = tpacket_destruct_skb;
__packet_set_status(po, ph, TP_STATUS_SENDING);
packet_inc_pending(&po->tx_ring);
status = TP_STATUS_SEND_REQUEST;
err = po->xmit(skb);
if (unlikely(err > 0)) {
err = net_xmit_errno(err);
if (err && __packet_get_status(po, ph) ==
TP_STATUS_AVAILABLE) {
/* skb was destructed already */
skb = NULL;
goto out_status;
}
/*
* skb was dropped but not destructed yet;
* let's treat it like congestion or err < 0
*/
err = 0;
}
packet_increment_head(&po->tx_ring);
len_sum += tp_len;
} while (likely((ph != NULL) ||
/* Note: packet_read_pending() might be slow if we have
* to call it as it's per_cpu variable, but in fast-path
* we already short-circuit the loop with the first
* condition, and luckily don't have to go that path
* anyway.
*/
(need_wait && packet_read_pending(&po->tx_ring))));
err = len_sum;
goto out_put;
out_status:
__packet_set_status(po, ph, status);
kfree_skb(skb);
out_put:
dev_put(dev);
out:
mutex_unlock(&po->pg_vec_lock);
return err;
}
static struct sk_buff *packet_alloc_skb(struct sock *sk, size_t prepad,
size_t reserve, size_t len,
size_t linear, int noblock,
int *err)
{
struct sk_buff *skb;
/* Under a page? Don't bother with paged skb. */
if (prepad + len < PAGE_SIZE || !linear)
linear = len;
skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
err, 0);
if (!skb)
return NULL;
skb_reserve(skb, reserve);
skb_put(skb, linear);
skb->data_len = len - linear;
skb->len += len - linear;
return skb;
}
static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
DECLARE_SOCKADDR(struct sockaddr_ll *, saddr, msg->msg_name);
struct sk_buff *skb;
struct net_device *dev;
__be16 proto;
unsigned char *addr = NULL;
int err, reserve = 0;
struct sockcm_cookie sockc;
struct virtio_net_hdr vnet_hdr = { 0 };
int offset = 0;
struct packet_sock *po = pkt_sk(sk);
bool has_vnet_hdr = false;
int hlen, tlen, linear;
int extra_len = 0;
/*
* Get and verify the address.
*/
if (likely(saddr == NULL)) {
dev = packet_cached_dev_get(po);
proto = po->num;
} else {
err = -EINVAL;
if (msg->msg_namelen < sizeof(struct sockaddr_ll))
goto out;
if (msg->msg_namelen < (saddr->sll_halen + offsetof(struct sockaddr_ll, sll_addr)))
goto out;
proto = saddr->sll_protocol;
dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
if (sock->type == SOCK_DGRAM) {
if (dev && msg->msg_namelen < dev->addr_len +
offsetof(struct sockaddr_ll, sll_addr))
goto out_unlock;
addr = saddr->sll_addr;
}
}
err = -ENXIO;
if (unlikely(dev == NULL))
goto out_unlock;
err = -ENETDOWN;
if (unlikely(!(dev->flags & IFF_UP)))
goto out_unlock;
sockcm_init(&sockc, sk);
sockc.mark = sk->sk_mark;
if (msg->msg_controllen) {
err = sock_cmsg_send(sk, msg, &sockc);
if (unlikely(err))
goto out_unlock;
}
if (sock->type == SOCK_RAW)
reserve = dev->hard_header_len;
if (po->has_vnet_hdr) {
err = packet_snd_vnet_parse(msg, &len, &vnet_hdr);
if (err)
goto out_unlock;
has_vnet_hdr = true;
}
if (unlikely(sock_flag(sk, SOCK_NOFCS))) {
if (!netif_supports_nofcs(dev)) {
err = -EPROTONOSUPPORT;
goto out_unlock;
}
extra_len = 4; /* We're doing our own CRC */
}
err = -EMSGSIZE;
if (!vnet_hdr.gso_type &&
(len > dev->mtu + reserve + VLAN_HLEN + extra_len))
goto out_unlock;
err = -ENOBUFS;
hlen = LL_RESERVED_SPACE(dev);
tlen = dev->needed_tailroom;
linear = __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len);
linear = max(linear, min_t(int, len, dev->hard_header_len));
skb = packet_alloc_skb(sk, hlen + tlen, hlen, len, linear,
msg->msg_flags & MSG_DONTWAIT, &err);
if (skb == NULL)
goto out_unlock;
skb_reset_network_header(skb);
err = -EINVAL;
if (sock->type == SOCK_DGRAM) {
offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len);
if (unlikely(offset < 0))
goto out_free;
} else if (reserve) {
skb_reserve(skb, -reserve);
if (len < reserve + sizeof(struct ipv6hdr) &&
dev->min_header_len != dev->hard_header_len)
skb_reset_network_header(skb);
}
/* Returns -EFAULT on error */
err = skb_copy_datagram_from_iter(skb, offset, &msg->msg_iter, len);
if (err)
goto out_free;
if (sock->type == SOCK_RAW &&
!dev_validate_header(dev, skb->data, len)) {
err = -EINVAL;
goto out_free;
}
skb_setup_tx_timestamp(skb, sockc.tsflags);
if (!vnet_hdr.gso_type && (len > dev->mtu + reserve + extra_len) &&
!packet_extra_vlan_len_allowed(dev, skb)) {
err = -EMSGSIZE;
goto out_free;
}
skb->protocol = proto;
skb->dev = dev;
skb->priority = sk->sk_priority;
skb->mark = sockc.mark;
skb->tstamp = sockc.transmit_time;
if (has_vnet_hdr) {
err = virtio_net_hdr_to_skb(skb, &vnet_hdr, vio_le());
if (err)
goto out_free;
len += sizeof(vnet_hdr);
virtio_net_hdr_set_proto(skb, &vnet_hdr);
}
packet_parse_headers(skb, sock);
if (unlikely(extra_len == 4))
skb->no_fcs = 1;
err = po->xmit(skb);
if (err > 0 && (err = net_xmit_errno(err)) != 0)
goto out_unlock;
dev_put(dev);
return len;
out_free:
kfree_skb(skb);
out_unlock:
if (dev)
dev_put(dev);
out:
return err;
}
static int packet_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct packet_sock *po = pkt_sk(sk);
if (po->tx_ring.pg_vec)
return tpacket_snd(po, msg);
else
return packet_snd(sock, msg, len);
}
/*
* Close a PACKET socket. This is fairly simple. We immediately go
* to 'closed' state and remove our protocol entry in the device list.
*/
static int packet_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct packet_sock *po;
struct packet_fanout *f;
struct net *net;
union tpacket_req_u req_u;
if (!sk)
return 0;
net = sock_net(sk);
po = pkt_sk(sk);
mutex_lock(&net->packet.sklist_lock);
sk_del_node_init_rcu(sk);
mutex_unlock(&net->packet.sklist_lock);
preempt_disable();
sock_prot_inuse_add(net, sk->sk_prot, -1);
preempt_enable();
spin_lock(&po->bind_lock);
unregister_prot_hook(sk, false);
packet_cached_dev_reset(po);
if (po->prot_hook.dev) {
dev_put(po->prot_hook.dev);
po->prot_hook.dev = NULL;
}
spin_unlock(&po->bind_lock);
packet_flush_mclist(sk);
lock_sock(sk);
if (po->rx_ring.pg_vec) {
memset(&req_u, 0, sizeof(req_u));
packet_set_ring(sk, &req_u, 1, 0);
}
if (po->tx_ring.pg_vec) {
memset(&req_u, 0, sizeof(req_u));
packet_set_ring(sk, &req_u, 1, 1);
}
release_sock(sk);
f = fanout_release(sk);
synchronize_net();
kfree(po->rollover);
if (f) {
fanout_release_data(f);
kfree(f);
}
/*
* Now the socket is dead. No more input will appear.
*/
sock_orphan(sk);
sock->sk = NULL;
/* Purge queues */
skb_queue_purge(&sk->sk_receive_queue);
packet_free_pending(po);
sk_refcnt_debug_release(sk);
sock_put(sk);
return 0;
}
/*
* Attach a packet hook.
*/
static int packet_do_bind(struct sock *sk, const char *name, int ifindex,
__be16 proto)
{
struct packet_sock *po = pkt_sk(sk);
struct net_device *dev_curr;
__be16 proto_curr;
bool need_rehook;
struct net_device *dev = NULL;
int ret = 0;
bool unlisted = false;
lock_sock(sk);
spin_lock(&po->bind_lock);
rcu_read_lock();
if (po->fanout) {
ret = -EINVAL;
goto out_unlock;
}
if (name) {
dev = dev_get_by_name_rcu(sock_net(sk), name);
if (!dev) {
ret = -ENODEV;
goto out_unlock;
}
} else if (ifindex) {
dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
if (!dev) {
ret = -ENODEV;
goto out_unlock;
}
}
if (dev)
dev_hold(dev);
proto_curr = po->prot_hook.type;
dev_curr = po->prot_hook.dev;
need_rehook = proto_curr != proto || dev_curr != dev;
if (need_rehook) {
if (po->running) {
rcu_read_unlock();
/* prevents packet_notifier() from calling
* register_prot_hook()
*/
po->num = 0;
__unregister_prot_hook(sk, true);
rcu_read_lock();
dev_curr = po->prot_hook.dev;
if (dev)
unlisted = !dev_get_by_index_rcu(sock_net(sk),
dev->ifindex);
}
BUG_ON(po->running);
po->num = proto;
po->prot_hook.type = proto;
if (unlikely(unlisted)) {
dev_put(dev);
po->prot_hook.dev = NULL;
po->ifindex = -1;
packet_cached_dev_reset(po);
} else {
po->prot_hook.dev = dev;
po->ifindex = dev ? dev->ifindex : 0;
packet_cached_dev_assign(po, dev);
}
}
if (dev_curr)
dev_put(dev_curr);
if (proto == 0 || !need_rehook)
goto out_unlock;
if (!unlisted && (!dev || (dev->flags & IFF_UP))) {
register_prot_hook(sk);
} else {
sk->sk_err = ENETDOWN;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_error_report(sk);
}
out_unlock:
rcu_read_unlock();
spin_unlock(&po->bind_lock);
release_sock(sk);
return ret;
}
/*
* Bind a packet socket to a device
*/
static int packet_bind_spkt(struct socket *sock, struct sockaddr *uaddr,
int addr_len)
{
struct sock *sk = sock->sk;
char name[sizeof(uaddr->sa_data) + 1];
/*
* Check legality
*/
if (addr_len != sizeof(struct sockaddr))
return -EINVAL;
/* uaddr->sa_data comes from the userspace, it's not guaranteed to be
* zero-terminated.
*/
memcpy(name, uaddr->sa_data, sizeof(uaddr->sa_data));
name[sizeof(uaddr->sa_data)] = 0;
return packet_do_bind(sk, name, 0, pkt_sk(sk)->num);
}
static int packet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
struct sockaddr_ll *sll = (struct sockaddr_ll *)uaddr;
struct sock *sk = sock->sk;
/*
* Check legality
*/
if (addr_len < sizeof(struct sockaddr_ll))
return -EINVAL;
if (sll->sll_family != AF_PACKET)
return -EINVAL;
return packet_do_bind(sk, NULL, sll->sll_ifindex,
sll->sll_protocol ? : pkt_sk(sk)->num);
}
static struct proto packet_proto = {
.name = "PACKET",
.owner = THIS_MODULE,
.obj_size = sizeof(struct packet_sock),
};
/*
* Create a packet of type SOCK_PACKET.
*/
static int packet_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct sock *sk;
struct packet_sock *po;
__be16 proto = (__force __be16)protocol; /* weird, but documented */
int err;
if (!ns_capable(net->user_ns, CAP_NET_RAW))
return -EPERM;
if (sock->type != SOCK_DGRAM && sock->type != SOCK_RAW &&
sock->type != SOCK_PACKET)
return -ESOCKTNOSUPPORT;
sock->state = SS_UNCONNECTED;
err = -ENOBUFS;
sk = sk_alloc(net, PF_PACKET, GFP_KERNEL, &packet_proto, kern);
if (sk == NULL)
goto out;
sock->ops = &packet_ops;
if (sock->type == SOCK_PACKET)
sock->ops = &packet_ops_spkt;
sock_init_data(sock, sk);
po = pkt_sk(sk);
init_completion(&po->skb_completion);
sk->sk_family = PF_PACKET;
po->num = proto;
po->xmit = dev_queue_xmit;
err = packet_alloc_pending(po);
if (err)
goto out2;
packet_cached_dev_reset(po);
sk->sk_destruct = packet_sock_destruct;
sk_refcnt_debug_inc(sk);
/*
* Attach a protocol block
*/
spin_lock_init(&po->bind_lock);
mutex_init(&po->pg_vec_lock);
po->rollover = NULL;
po->prot_hook.func = packet_rcv;
if (sock->type == SOCK_PACKET)
po->prot_hook.func = packet_rcv_spkt;
po->prot_hook.af_packet_priv = sk;
if (proto) {
po->prot_hook.type = proto;
__register_prot_hook(sk);
}
mutex_lock(&net->packet.sklist_lock);
sk_add_node_tail_rcu(sk, &net->packet.sklist);
mutex_unlock(&net->packet.sklist_lock);
preempt_disable();
sock_prot_inuse_add(net, &packet_proto, 1);
preempt_enable();
return 0;
out2:
sk_free(sk);
out:
return err;
}
/*
* Pull a packet from our receive queue and hand it to the user.
* If necessary we block.
*/
static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
{
struct sock *sk = sock->sk;
struct sk_buff *skb;
int copied, err;
int vnet_hdr_len = 0;
unsigned int origlen = 0;
err = -EINVAL;
if (flags & ~(MSG_PEEK|MSG_DONTWAIT|MSG_TRUNC|MSG_CMSG_COMPAT|MSG_ERRQUEUE))
goto out;
#if 0
/* What error should we return now? EUNATTACH? */
if (pkt_sk(sk)->ifindex < 0)
return -ENODEV;
#endif
if (flags & MSG_ERRQUEUE) {
err = sock_recv_errqueue(sk, msg, len,
SOL_PACKET, PACKET_TX_TIMESTAMP);
goto out;
}
/*
* Call the generic datagram receiver. This handles all sorts
* of horrible races and re-entrancy so we can forget about it
* in the protocol layers.
*
* Now it will return ENETDOWN, if device have just gone down,
* but then it will block.
*/
skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &err);
/*
* An error occurred so return it. Because skb_recv_datagram()
* handles the blocking we don't see and worry about blocking
* retries.
*/
if (skb == NULL)
goto out;
packet_rcv_try_clear_pressure(pkt_sk(sk));
if (pkt_sk(sk)->has_vnet_hdr) {
err = packet_rcv_vnet(msg, skb, &len);
if (err)
goto out_free;
vnet_hdr_len = sizeof(struct virtio_net_hdr);
}
/* You lose any data beyond the buffer you gave. If it worries
* a user program they can ask the device for its MTU
* anyway.
*/
copied = skb->len;
if (copied > len) {
copied = len;
msg->msg_flags |= MSG_TRUNC;
}
err = skb_copy_datagram_msg(skb, 0, msg, copied);
if (err)
goto out_free;
if (sock->type != SOCK_PACKET) {
struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
/* Original length was stored in sockaddr_ll fields */
origlen = PACKET_SKB_CB(skb)->sa.origlen;
sll->sll_family = AF_PACKET;
sll->sll_protocol = skb->protocol;
}
sock_recv_ts_and_drops(msg, sk, skb);
if (msg->msg_name) {
int copy_len;
/* If the address length field is there to be filled
* in, we fill it in now.
*/
if (sock->type == SOCK_PACKET) {
__sockaddr_check_size(sizeof(struct sockaddr_pkt));
msg->msg_namelen = sizeof(struct sockaddr_pkt);
copy_len = msg->msg_namelen;
} else {
struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
msg->msg_namelen = sll->sll_halen +
offsetof(struct sockaddr_ll, sll_addr);
copy_len = msg->msg_namelen;
if (msg->msg_namelen < sizeof(struct sockaddr_ll)) {
memset(msg->msg_name +
offsetof(struct sockaddr_ll, sll_addr),
0, sizeof(sll->sll_addr));
msg->msg_namelen = sizeof(struct sockaddr_ll);
}
}
memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa, copy_len);
}
if (pkt_sk(sk)->auxdata) {
struct tpacket_auxdata aux;
aux.tp_status = TP_STATUS_USER;
if (skb->ip_summed == CHECKSUM_PARTIAL)
aux.tp_status |= TP_STATUS_CSUMNOTREADY;
else if (skb->pkt_type != PACKET_OUTGOING &&
(skb->ip_summed == CHECKSUM_COMPLETE ||
skb_csum_unnecessary(skb)))
aux.tp_status |= TP_STATUS_CSUM_VALID;
aux.tp_len = origlen;
aux.tp_snaplen = skb->len;
aux.tp_mac = 0;
aux.tp_net = skb_network_offset(skb);
if (skb_vlan_tag_present(skb)) {
aux.tp_vlan_tci = skb_vlan_tag_get(skb);
aux.tp_vlan_tpid = ntohs(skb->vlan_proto);
aux.tp_status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
} else {
aux.tp_vlan_tci = 0;
aux.tp_vlan_tpid = 0;
}
put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);
}
/*
* Free or return the buffer as appropriate. Again this
* hides all the races and re-entrancy issues from us.
*/
err = vnet_hdr_len + ((flags&MSG_TRUNC) ? skb->len : copied);
out_free:
skb_free_datagram(sk, skb);
out:
return err;
}
static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr,
int peer)
{
struct net_device *dev;
struct sock *sk = sock->sk;
if (peer)
return -EOPNOTSUPP;
uaddr->sa_family = AF_PACKET;
memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data));
rcu_read_lock();
dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
if (dev)
strlcpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data));
rcu_read_unlock();
return sizeof(*uaddr);
}
static int packet_getname(struct socket *sock, struct sockaddr *uaddr,
int peer)
{
struct net_device *dev;
struct sock *sk = sock->sk;
struct packet_sock *po = pkt_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_ll *, sll, uaddr);
if (peer)
return -EOPNOTSUPP;
sll->sll_family = AF_PACKET;
sll->sll_ifindex = po->ifindex;
sll->sll_protocol = po->num;
sll->sll_pkttype = 0;
rcu_read_lock();
dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex);
if (dev) {
sll->sll_hatype = dev->type;
sll->sll_halen = dev->addr_len;
memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
} else {
sll->sll_hatype = 0; /* Bad: we have no ARPHRD_UNSPEC */
sll->sll_halen = 0;
}
rcu_read_unlock();
return offsetof(struct sockaddr_ll, sll_addr) + sll->sll_halen;
}
static int packet_dev_mc(struct net_device *dev, struct packet_mclist *i,
int what)
{
switch (i->type) {
case PACKET_MR_MULTICAST:
if (i->alen != dev->addr_len)
return -EINVAL;
if (what > 0)
return dev_mc_add(dev, i->addr);
else
return dev_mc_del(dev, i->addr);
break;
case PACKET_MR_PROMISC:
return dev_set_promiscuity(dev, what);
case PACKET_MR_ALLMULTI:
return dev_set_allmulti(dev, what);
case PACKET_MR_UNICAST:
if (i->alen != dev->addr_len)
return -EINVAL;
if (what > 0)
return dev_uc_add(dev, i->addr);
else
return dev_uc_del(dev, i->addr);
break;
default:
break;
}
return 0;
}
static void packet_dev_mclist_delete(struct net_device *dev,
struct packet_mclist **mlp)
{
struct packet_mclist *ml;
while ((ml = *mlp) != NULL) {
if (ml->ifindex == dev->ifindex) {
packet_dev_mc(dev, ml, -1);
*mlp = ml->next;
kfree(ml);
} else
mlp = &ml->next;
}
}
static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
{
struct packet_sock *po = pkt_sk(sk);
struct packet_mclist *ml, *i;
struct net_device *dev;
int err;
rtnl_lock();
err = -ENODEV;
dev = __dev_get_by_index(sock_net(sk), mreq->mr_ifindex);
if (!dev)
goto done;
err = -EINVAL;
if (mreq->mr_alen > dev->addr_len)
goto done;
err = -ENOBUFS;
i = kmalloc(sizeof(*i), GFP_KERNEL);
if (i == NULL)
goto done;
err = 0;
for (ml = po->mclist; ml; ml = ml->next) {
if (ml->ifindex == mreq->mr_ifindex &&
ml->type == mreq->mr_type &&
ml->alen == mreq->mr_alen &&
memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
ml->count++;
/* Free the new element ... */
kfree(i);
goto done;
}
}
i->type = mreq->mr_type;
i->ifindex = mreq->mr_ifindex;
i->alen = mreq->mr_alen;
memcpy(i->addr, mreq->mr_address, i->alen);
memset(i->addr + i->alen, 0, sizeof(i->addr) - i->alen);
i->count = 1;
i->next = po->mclist;
po->mclist = i;
err = packet_dev_mc(dev, i, 1);
if (err) {
po->mclist = i->next;
kfree(i);
}
done:
rtnl_unlock();
return err;
}
static int packet_mc_drop(struct sock *sk, struct packet_mreq_max *mreq)
{
struct packet_mclist *ml, **mlp;
rtnl_lock();
for (mlp = &pkt_sk(sk)->mclist; (ml = *mlp) != NULL; mlp = &ml->next) {
if (ml->ifindex == mreq->mr_ifindex &&
ml->type == mreq->mr_type &&
ml->alen == mreq->mr_alen &&
memcmp(ml->addr, mreq->mr_address, ml->alen) == 0) {
if (--ml->count == 0) {
struct net_device *dev;
*mlp = ml->next;
dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
if (dev)
packet_dev_mc(dev, ml, -1);
kfree(ml);
}
break;
}
}
rtnl_unlock();
return 0;
}
static void packet_flush_mclist(struct sock *sk)
{
struct packet_sock *po = pkt_sk(sk);
struct packet_mclist *ml;
if (!po->mclist)
return;
rtnl_lock();
while ((ml = po->mclist) != NULL) {
struct net_device *dev;
po->mclist = ml->next;
dev = __dev_get_by_index(sock_net(sk), ml->ifindex);
if (dev != NULL)
packet_dev_mc(dev, ml, -1);
kfree(ml);
}
rtnl_unlock();
}
static int
packet_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
{
struct sock *sk = sock->sk;
struct packet_sock *po = pkt_sk(sk);
int ret;
if (level != SOL_PACKET)
return -ENOPROTOOPT;
switch (optname) {
case PACKET_ADD_MEMBERSHIP:
case PACKET_DROP_MEMBERSHIP:
{
struct packet_mreq_max mreq;
int len = optlen;
memset(&mreq, 0, sizeof(mreq));
if (len < sizeof(struct packet_mreq))
return -EINVAL;
if (len > sizeof(mreq))
len = sizeof(mreq);
if (copy_from_user(&mreq, optval, len))
return -EFAULT;
if (len < (mreq.mr_alen + offsetof(struct packet_mreq, mr_address)))
return -EINVAL;
if (optname == PACKET_ADD_MEMBERSHIP)
ret = packet_mc_add(sk, &mreq);
else
ret = packet_mc_drop(sk, &mreq);
return ret;
}
case PACKET_RX_RING:
case PACKET_TX_RING:
{
union tpacket_req_u req_u;
int len;
lock_sock(sk);
switch (po->tp_version) {
case TPACKET_V1:
case TPACKET_V2:
len = sizeof(req_u.req);
break;
case TPACKET_V3:
default:
len = sizeof(req_u.req3);
break;
}
if (optlen < len) {
ret = -EINVAL;
} else {
if (copy_from_user(&req_u.req, optval, len))
ret = -EFAULT;
else
ret = packet_set_ring(sk, &req_u, 0,
optname == PACKET_TX_RING);
}
release_sock(sk);
return ret;
}
case PACKET_COPY_THRESH:
{
int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
pkt_sk(sk)->copy_thresh = val;
return 0;
}
case PACKET_VERSION:
{
int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
switch (val) {
case TPACKET_V1:
case TPACKET_V2:
case TPACKET_V3:
break;
default:
return -EINVAL;
}
lock_sock(sk);
if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
ret = -EBUSY;
} else {
po->tp_version = val;
ret = 0;
}
release_sock(sk);
return ret;
}
case PACKET_RESERVE:
{
unsigned int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
if (val > INT_MAX)
return -EINVAL;
lock_sock(sk);
if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
ret = -EBUSY;
} else {
po->tp_reserve = val;
ret = 0;
}
release_sock(sk);
return ret;
}
case PACKET_LOSS:
{
unsigned int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
lock_sock(sk);
if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
ret = -EBUSY;
} else {
po->tp_loss = !!val;
ret = 0;
}
release_sock(sk);
return ret;
}
case PACKET_AUXDATA:
{
int val;
if (optlen < sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
lock_sock(sk);
po->auxdata = !!val;
release_sock(sk);
return 0;
}
case PACKET_ORIGDEV:
{
int val;
if (optlen < sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
lock_sock(sk);
po->origdev = !!val;
release_sock(sk);
return 0;
}
case PACKET_VNET_HDR:
{
int val;
if (sock->type != SOCK_RAW)
return -EINVAL;
if (optlen < sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
lock_sock(sk);
if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
ret = -EBUSY;
} else {
po->has_vnet_hdr = !!val;
ret = 0;
}
release_sock(sk);
return ret;
}
case PACKET_TIMESTAMP:
{
int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
po->tp_tstamp = val;
return 0;
}
case PACKET_FANOUT:
{
int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
return fanout_add(sk, val & 0xffff, val >> 16);
}
case PACKET_FANOUT_DATA:
{
if (!po->fanout)
return -EINVAL;
return fanout_set_data(po, optval, optlen);
}
case PACKET_IGNORE_OUTGOING:
{
int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
if (val < 0 || val > 1)
return -EINVAL;
po->prot_hook.ignore_outgoing = !!val;
return 0;
}
case PACKET_TX_HAS_OFF:
{
unsigned int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
lock_sock(sk);
if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
ret = -EBUSY;
} else {
po->tp_tx_has_off = !!val;
ret = 0;
}
release_sock(sk);
return 0;
}
case PACKET_QDISC_BYPASS:
{
int val;
if (optlen != sizeof(val))
return -EINVAL;
if (copy_from_user(&val, optval, sizeof(val)))
return -EFAULT;
po->xmit = val ? packet_direct_xmit : dev_queue_xmit;
return 0;
}
default:
return -ENOPROTOOPT;
}
}
static int packet_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
int len;
int val, lv = sizeof(val);
struct sock *sk = sock->sk;
struct packet_sock *po = pkt_sk(sk);
void *data = &val;
union tpacket_stats_u st;
struct tpacket_rollover_stats rstats;
int drops;
if (level != SOL_PACKET)
return -ENOPROTOOPT;
if (get_user(len, optlen))
return -EFAULT;
if (len < 0)
return -EINVAL;
switch (optname) {
case PACKET_STATISTICS:
spin_lock_bh(&sk->sk_receive_queue.lock);
memcpy(&st, &po->stats, sizeof(st));
memset(&po->stats, 0, sizeof(po->stats));
spin_unlock_bh(&sk->sk_receive_queue.lock);
drops = atomic_xchg(&po->tp_drops, 0);
if (po->tp_version == TPACKET_V3) {
lv = sizeof(struct tpacket_stats_v3);
st.stats3.tp_drops = drops;
st.stats3.tp_packets += drops;
data = &st.stats3;
} else {
lv = sizeof(struct tpacket_stats);
st.stats1.tp_drops = drops;
st.stats1.tp_packets += drops;
data = &st.stats1;
}
break;
case PACKET_AUXDATA:
val = po->auxdata;
break;
case PACKET_ORIGDEV:
val = po->origdev;
break;
case PACKET_VNET_HDR:
val = po->has_vnet_hdr;
break;
case PACKET_VERSION:
val = po->tp_version;
break;
case PACKET_HDRLEN:
if (len > sizeof(int))
len = sizeof(int);
if (len < sizeof(int))
return -EINVAL;
if (copy_from_user(&val, optval, len))
return -EFAULT;
switch (val) {
case TPACKET_V1:
val = sizeof(struct tpacket_hdr);
break;
case TPACKET_V2:
val = sizeof(struct tpacket2_hdr);
break;
case TPACKET_V3:
val = sizeof(struct tpacket3_hdr);
break;
default:
return -EINVAL;
}
break;
case PACKET_RESERVE:
val = po->tp_reserve;
break;
case PACKET_LOSS:
val = po->tp_loss;
break;
case PACKET_TIMESTAMP:
val = po->tp_tstamp;
break;
case PACKET_FANOUT:
val = (po->fanout ?
((u32)po->fanout->id |
((u32)po->fanout->type << 16) |
((u32)po->fanout->flags << 24)) :
0);
break;
case PACKET_IGNORE_OUTGOING:
val = po->prot_hook.ignore_outgoing;
break;
case PACKET_ROLLOVER_STATS:
if (!po->rollover)
return -EINVAL;
rstats.tp_all = atomic_long_read(&po->rollover->num);
rstats.tp_huge = atomic_long_read(&po->rollover->num_huge);
rstats.tp_failed = atomic_long_read(&po->rollover->num_failed);
data = &rstats;
lv = sizeof(rstats);
break;
case PACKET_TX_HAS_OFF:
val = po->tp_tx_has_off;
break;
case PACKET_QDISC_BYPASS:
val = packet_use_direct_xmit(po);
break;
default:
return -ENOPROTOOPT;
}
if (len > lv)
len = lv;
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, data, len))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
static int compat_packet_setsockopt(struct socket *sock, int level, int optname,
char __user *optval, unsigned int optlen)
{
struct packet_sock *po = pkt_sk(sock->sk);
if (level != SOL_PACKET)
return -ENOPROTOOPT;
if (optname == PACKET_FANOUT_DATA &&
po->fanout && po->fanout->type == PACKET_FANOUT_CBPF) {
optval = (char __user *)get_compat_bpf_fprog(optval);
if (!optval)
return -EFAULT;
optlen = sizeof(struct sock_fprog);
}
return packet_setsockopt(sock, level, optname, optval, optlen);
}
#endif
static int packet_notifier(struct notifier_block *this,
unsigned long msg, void *ptr)
{
struct sock *sk;
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct net *net = dev_net(dev);
rcu_read_lock();
sk_for_each_rcu(sk, &net->packet.sklist) {
struct packet_sock *po = pkt_sk(sk);
switch (msg) {
case NETDEV_UNREGISTER:
if (po->mclist)
packet_dev_mclist_delete(dev, &po->mclist);
/* fallthrough */
case NETDEV_DOWN:
if (dev->ifindex == po->ifindex) {
spin_lock(&po->bind_lock);
if (po->running) {
__unregister_prot_hook(sk, false);
sk->sk_err = ENETDOWN;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_error_report(sk);
}
if (msg == NETDEV_UNREGISTER) {
packet_cached_dev_reset(po);
po->ifindex = -1;
if (po->prot_hook.dev)
dev_put(po->prot_hook.dev);
po->prot_hook.dev = NULL;
}
spin_unlock(&po->bind_lock);
}
break;
case NETDEV_UP:
if (dev->ifindex == po->ifindex) {
spin_lock(&po->bind_lock);
if (po->num)
register_prot_hook(sk);
spin_unlock(&po->bind_lock);
}
break;
}
}
rcu_read_unlock();
return NOTIFY_DONE;
}
static int packet_ioctl(struct socket *sock, unsigned int cmd,
unsigned long arg)
{
struct sock *sk = sock->sk;
switch (cmd) {
case SIOCOUTQ:
{
int amount = sk_wmem_alloc_get(sk);
return put_user(amount, (int __user *)arg);
}
case SIOCINQ:
{
struct sk_buff *skb;
int amount = 0;
spin_lock_bh(&sk->sk_receive_queue.lock);
skb = skb_peek(&sk->sk_receive_queue);
if (skb)
amount = skb->len;
spin_unlock_bh(&sk->sk_receive_queue.lock);
return put_user(amount, (int __user *)arg);
}
#ifdef CONFIG_INET
case SIOCADDRT:
case SIOCDELRT:
case SIOCDARP:
case SIOCGARP:
case SIOCSARP:
case SIOCGIFADDR:
case SIOCSIFADDR:
case SIOCGIFBRDADDR:
case SIOCSIFBRDADDR:
case SIOCGIFNETMASK:
case SIOCSIFNETMASK:
case SIOCGIFDSTADDR:
case SIOCSIFDSTADDR:
case SIOCSIFFLAGS:
return inet_dgram_ops.ioctl(sock, cmd, arg);
#endif
default:
return -ENOIOCTLCMD;
}
return 0;
}
static __poll_t packet_poll(struct file *file, struct socket *sock,
poll_table *wait)
{
struct sock *sk = sock->sk;
struct packet_sock *po = pkt_sk(sk);
__poll_t mask = datagram_poll(file, sock, wait);
spin_lock_bh(&sk->sk_receive_queue.lock);
if (po->rx_ring.pg_vec) {
if (!packet_previous_rx_frame(po, &po->rx_ring,
TP_STATUS_KERNEL))
mask |= EPOLLIN | EPOLLRDNORM;
}
packet_rcv_try_clear_pressure(po);
spin_unlock_bh(&sk->sk_receive_queue.lock);
spin_lock_bh(&sk->sk_write_queue.lock);
if (po->tx_ring.pg_vec) {
if (packet_current_frame(po, &po->tx_ring, TP_STATUS_AVAILABLE))
mask |= EPOLLOUT | EPOLLWRNORM;
}
spin_unlock_bh(&sk->sk_write_queue.lock);
return mask;
}
/* Dirty? Well, I still did not learn better way to account
* for user mmaps.
*/
static void packet_mm_open(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct socket *sock = file->private_data;
struct sock *sk = sock->sk;
if (sk)
atomic_inc(&pkt_sk(sk)->mapped);
}
static void packet_mm_close(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct socket *sock = file->private_data;
struct sock *sk = sock->sk;
if (sk)
atomic_dec(&pkt_sk(sk)->mapped);
}
static const struct vm_operations_struct packet_mmap_ops = {
.open = packet_mm_open,
.close = packet_mm_close,
};
static void free_pg_vec(struct pgv *pg_vec, unsigned int order,
unsigned int len)
{
int i;
for (i = 0; i < len; i++) {
if (likely(pg_vec[i].buffer)) {
if (is_vmalloc_addr(pg_vec[i].buffer))
vfree(pg_vec[i].buffer);
else
free_pages((unsigned long)pg_vec[i].buffer,
order);
pg_vec[i].buffer = NULL;
}
}
kfree(pg_vec);
}
static char *alloc_one_pg_vec_page(unsigned long order)
{
char *buffer;
gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP |
__GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY;
buffer = (char *) __get_free_pages(gfp_flags, order);
if (buffer)
return buffer;
/* __get_free_pages failed, fall back to vmalloc */
buffer = vzalloc(array_size((1 << order), PAGE_SIZE));
if (buffer)
return buffer;
/* vmalloc failed, lets dig into swap here */
gfp_flags &= ~__GFP_NORETRY;
buffer = (char *) __get_free_pages(gfp_flags, order);
if (buffer)
return buffer;
/* complete and utter failure */
return NULL;
}
static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
{
unsigned int block_nr = req->tp_block_nr;
struct pgv *pg_vec;
int i;
pg_vec = kcalloc(block_nr, sizeof(struct pgv), GFP_KERNEL | __GFP_NOWARN);
if (unlikely(!pg_vec))
goto out;
for (i = 0; i < block_nr; i++) {
pg_vec[i].buffer = alloc_one_pg_vec_page(order);
if (unlikely(!pg_vec[i].buffer))
goto out_free_pgvec;
}
out:
return pg_vec;
out_free_pgvec:
free_pg_vec(pg_vec, order, block_nr);
pg_vec = NULL;
goto out;
}
static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
int closing, int tx_ring)
{
struct pgv *pg_vec = NULL;
struct packet_sock *po = pkt_sk(sk);
unsigned long *rx_owner_map = NULL;
int was_running, order = 0;
struct packet_ring_buffer *rb;
struct sk_buff_head *rb_queue;
__be16 num;
int err = -EINVAL;
/* Added to avoid minimal code churn */
struct tpacket_req *req = &req_u->req;
rb = tx_ring ? &po->tx_ring : &po->rx_ring;
rb_queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
err = -EBUSY;
if (!closing) {
if (atomic_read(&po->mapped))
goto out;
if (packet_read_pending(rb))
goto out;
}
if (req->tp_block_nr) {
unsigned int min_frame_size;
/* Sanity tests and some calculations */
err = -EBUSY;
if (unlikely(rb->pg_vec))
goto out;
switch (po->tp_version) {
case TPACKET_V1:
po->tp_hdrlen = TPACKET_HDRLEN;
break;
case TPACKET_V2:
po->tp_hdrlen = TPACKET2_HDRLEN;
break;
case TPACKET_V3:
po->tp_hdrlen = TPACKET3_HDRLEN;
break;
}
err = -EINVAL;
if (unlikely((int)req->tp_block_size <= 0))
goto out;
if (unlikely(!PAGE_ALIGNED(req->tp_block_size)))
goto out;
min_frame_size = po->tp_hdrlen + po->tp_reserve;
if (po->tp_version >= TPACKET_V3 &&
req->tp_block_size <
BLK_PLUS_PRIV((u64)req_u->req3.tp_sizeof_priv) + min_frame_size)
goto out;
if (unlikely(req->tp_frame_size < min_frame_size))
goto out;
if (unlikely(req->tp_frame_size & (TPACKET_ALIGNMENT - 1)))
goto out;
rb->frames_per_block = req->tp_block_size / req->tp_frame_size;
if (unlikely(rb->frames_per_block == 0))
goto out;
if (unlikely(rb->frames_per_block > UINT_MAX / req->tp_block_nr))
goto out;
if (unlikely((rb->frames_per_block * req->tp_block_nr) !=
req->tp_frame_nr))
goto out;
err = -ENOMEM;
order = get_order(req->tp_block_size);
pg_vec = alloc_pg_vec(req, order);
if (unlikely(!pg_vec))
goto out;
switch (po->tp_version) {
case TPACKET_V3:
/* Block transmit is not supported yet */
if (!tx_ring) {
init_prb_bdqc(po, rb, pg_vec, req_u);
} else {
struct tpacket_req3 *req3 = &req_u->req3;
if (req3->tp_retire_blk_tov ||
req3->tp_sizeof_priv ||
req3->tp_feature_req_word) {
err = -EINVAL;
goto out_free_pg_vec;
}
}
break;
default:
if (!tx_ring) {
rx_owner_map = bitmap_alloc(req->tp_frame_nr,
GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO);
if (!rx_owner_map)
goto out_free_pg_vec;
}
break;
}
}
/* Done */
else {
err = -EINVAL;
if (unlikely(req->tp_frame_nr))
goto out;
}
/* Detach socket from network */
spin_lock(&po->bind_lock);
was_running = po->running;
num = po->num;
if (was_running) {
po->num = 0;
__unregister_prot_hook(sk, false);
}
spin_unlock(&po->bind_lock);
synchronize_net();
err = -EBUSY;
mutex_lock(&po->pg_vec_lock);
if (closing || atomic_read(&po->mapped) == 0) {
err = 0;
spin_lock_bh(&rb_queue->lock);
swap(rb->pg_vec, pg_vec);
if (po->tp_version <= TPACKET_V2)
swap(rb->rx_owner_map, rx_owner_map);
rb->frame_max = (req->tp_frame_nr - 1);
rb->head = 0;
rb->frame_size = req->tp_frame_size;
spin_unlock_bh(&rb_queue->lock);
swap(rb->pg_vec_order, order);
swap(rb->pg_vec_len, req->tp_block_nr);
rb->pg_vec_pages = req->tp_block_size/PAGE_SIZE;
po->prot_hook.func = (po->rx_ring.pg_vec) ?
tpacket_rcv : packet_rcv;
skb_queue_purge(rb_queue);
if (atomic_read(&po->mapped))
pr_err("packet_mmap: vma is busy: %d\n",
atomic_read(&po->mapped));
}
mutex_unlock(&po->pg_vec_lock);
spin_lock(&po->bind_lock);
if (was_running) {
po->num = num;
register_prot_hook(sk);
}
spin_unlock(&po->bind_lock);
if (pg_vec && (po->tp_version > TPACKET_V2)) {
/* Because we don't support block-based V3 on tx-ring */
if (!tx_ring)
prb_shutdown_retire_blk_timer(po, rb_queue);
}
out_free_pg_vec:
bitmap_free(rx_owner_map);
if (pg_vec)
free_pg_vec(pg_vec, order, req->tp_block_nr);
out:
return err;
}
static int packet_mmap(struct file *file, struct socket *sock,
struct vm_area_struct *vma)
{
struct sock *sk = sock->sk;
struct packet_sock *po = pkt_sk(sk);
unsigned long size, expected_size;
struct packet_ring_buffer *rb;
unsigned long start;
int err = -EINVAL;
int i;
if (vma->vm_pgoff)
return -EINVAL;
mutex_lock(&po->pg_vec_lock);
expected_size = 0;
for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
if (rb->pg_vec) {
expected_size += rb->pg_vec_len
* rb->pg_vec_pages
* PAGE_SIZE;
}
}
if (expected_size == 0)
goto out;
size = vma->vm_end - vma->vm_start;
if (size != expected_size)
goto out;
start = vma->vm_start;
for (rb = &po->rx_ring; rb <= &po->tx_ring; rb++) {
if (rb->pg_vec == NULL)
continue;
for (i = 0; i < rb->pg_vec_len; i++) {
struct page *page;
void *kaddr = rb->pg_vec[i].buffer;
int pg_num;
for (pg_num = 0; pg_num < rb->pg_vec_pages; pg_num++) {
page = pgv_to_page(kaddr);
err = vm_insert_page(vma, start, page);
if (unlikely(err))
goto out;
start += PAGE_SIZE;
kaddr += PAGE_SIZE;
}
}
}
atomic_inc(&po->mapped);
vma->vm_ops = &packet_mmap_ops;
err = 0;
out:
mutex_unlock(&po->pg_vec_lock);
return err;
}
static const struct proto_ops packet_ops_spkt = {
.family = PF_PACKET,
.owner = THIS_MODULE,
.release = packet_release,
.bind = packet_bind_spkt,
.connect = sock_no_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = packet_getname_spkt,
.poll = datagram_poll,
.ioctl = packet_ioctl,
.gettstamp = sock_gettstamp,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = sock_no_setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = packet_sendmsg_spkt,
.recvmsg = packet_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
static const struct proto_ops packet_ops = {
.family = PF_PACKET,
.owner = THIS_MODULE,
.release = packet_release,
.bind = packet_bind,
.connect = sock_no_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = packet_getname,
.poll = packet_poll,
.ioctl = packet_ioctl,
.gettstamp = sock_gettstamp,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = packet_setsockopt,
.getsockopt = packet_getsockopt,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_packet_setsockopt,
#endif
.sendmsg = packet_sendmsg,
.recvmsg = packet_recvmsg,
.mmap = packet_mmap,
.sendpage = sock_no_sendpage,
};
static const struct net_proto_family packet_family_ops = {
.family = PF_PACKET,
.create = packet_create,
.owner = THIS_MODULE,
};
static struct notifier_block packet_netdev_notifier = {
.notifier_call = packet_notifier,
};
#ifdef CONFIG_PROC_FS
static void *packet_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU)
{
struct net *net = seq_file_net(seq);
rcu_read_lock();
return seq_hlist_start_head_rcu(&net->packet.sklist, *pos);
}
static void *packet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct net *net = seq_file_net(seq);
return seq_hlist_next_rcu(v, &net->packet.sklist, pos);
}
static void packet_seq_stop(struct seq_file *seq, void *v)
__releases(RCU)
{
rcu_read_unlock();
}
static int packet_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN)
seq_puts(seq, "sk RefCnt Type Proto Iface R Rmem User Inode\n");
else {
struct sock *s = sk_entry(v);
const struct packet_sock *po = pkt_sk(s);
seq_printf(seq,
"%pK %-6d %-4d %04x %-5d %1d %-6u %-6u %-6lu\n",
s,
refcount_read(&s->sk_refcnt),
s->sk_type,
ntohs(po->num),
po->ifindex,
po->running,
atomic_read(&s->sk_rmem_alloc),
from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)),
sock_i_ino(s));
}
return 0;
}
static const struct seq_operations packet_seq_ops = {
.start = packet_seq_start,
.next = packet_seq_next,
.stop = packet_seq_stop,
.show = packet_seq_show,
};
#endif
static int __net_init packet_net_init(struct net *net)
{
mutex_init(&net->packet.sklist_lock);
INIT_HLIST_HEAD(&net->packet.sklist);
if (!proc_create_net("packet", 0, net->proc_net, &packet_seq_ops,
sizeof(struct seq_net_private)))
return -ENOMEM;
return 0;
}
static void __net_exit packet_net_exit(struct net *net)
{
remove_proc_entry("packet", net->proc_net);
WARN_ON_ONCE(!hlist_empty(&net->packet.sklist));
}
static struct pernet_operations packet_net_ops = {
.init = packet_net_init,
.exit = packet_net_exit,
};
static void __exit packet_exit(void)
{
unregister_netdevice_notifier(&packet_netdev_notifier);
unregister_pernet_subsys(&packet_net_ops);
sock_unregister(PF_PACKET);
proto_unregister(&packet_proto);
}
static int __init packet_init(void)
{
int rc;
rc = proto_register(&packet_proto, 0);
if (rc)
goto out;
rc = sock_register(&packet_family_ops);
if (rc)
goto out_proto;
rc = register_pernet_subsys(&packet_net_ops);
if (rc)
goto out_sock;
rc = register_netdevice_notifier(&packet_netdev_notifier);
if (rc)
goto out_pernet;
return 0;
out_pernet:
unregister_pernet_subsys(&packet_net_ops);
out_sock:
sock_unregister(PF_PACKET);
out_proto:
proto_unregister(&packet_proto);
out:
return rc;
}
module_init(packet_init);
module_exit(packet_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_PACKET);
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